Sanji, born as "Vinsmoke Sanji", is the chef of the straw hats pirates, the 3rd son of the Vinsmoke Family and the former prince of Germa kingdom. Aside from his cooking skills, he is also well known for his flirtatious and perverted behavior towards women. During the Whole Cake Island arc, he became the love interest of Charlotte Pudding.
Due to his chivarly and perverted nature, Sanji has developped interest in many women towards the series.
Sanji met Nami during his time as sous-chef in Baratie. He found her attractive and beautiful. He usually flirts with her as he does with every women. Nami often uses his infatuation towards her for her own advantage, which Sanji enjoys it. However, Nami does get annoyed at Sanji's perverted behavior and his declaration of love during serious moments, and doesn't hesitate to beat him up for it. Sanji is always kind and respectful towards her, as he adresses her as "Nami-san", which is reciprocrated by Nami, as he is the only one Nami does call by honorifics; addressing him as "Sanji-kun". Not only Nami respects Sanji as better cook, but also respects him for his chivarly, as during the Ennies Lobby arc, despite being defeated by Khalifa, Nami expressed admiration for Sanji's chivarly and respect towards women. In return, Sanji is quite protective of Nami, and doesn't hesitate to beat anyone who badmouths her, or does pervert things to her, such as Absalom, when he saw her naked, and tried to marry her during the Thriller Bark arc.
When the Big Mom's pirates tried to take Sanji away for his arranged marriage to Charlotte Pudding, Sanji accepted the proposal by freeing Nami, along with Chopper and Brook. After learning of Sanji's connection to the Vinsmoke Family and Germa 66, Nami offered Luffy to take part in the mission to rescue Sanji, feeling responsible for his kidnapping.
When Nami saw Sanji again, she was happy to see him again, but their excitement was short-lived as Sanji (reluctantly) tried to get them to leave Whole Cake Island by kicking Luffy away and acted as if he embraced his royal heritage. Nami was speechless and heart broken at Sanji's supposed change in personality as he went on to insult them because of their peasant status. Nami was shocked to see Sanji attack a non-retaliating Luffy while insulting the crew and their dreams, and was even scared when he gave her a vicious glare to silence her (something he never did before). After the confrontation, a tearful Nami approached Sanji and slapped him across the face while not using her usual "-kun" honorific for him, signifying a loss of respect. She angrily and sarcastically bid him farewell on his journey while Sanji is unable to look her in the eye, instead simply walking away after the strike to his cheek. As Sanji rode away in the carriage, Nami cried in earnest and even attempted to get Luffy to abandon trying to rescue Sanji. When his crewmates were captured by Big Mom's forces, Sanji believed he saved their life by agreeing to marry Pudding, until he learns of Pudding's deception,Big Mom' s plan to kill him and his family and the fact that Big mom never intended to keep her promise of not hurting his friends with him, as she planned to kill them after the setup wedding.
After coming to understand the situation, Nami was deeply saddened by Sanji's troubles and once again becomes determined to rescue him and bring him back to the crew at all costs. While she does tell him that she'll never forgive him for the despair he put her through, she's willing to put that aside for the sake of rescuing him. While taking the never forgiving part as a pierce to the heart, Sanji then mistook her claim of putting it aside as a proposal, and returned to his love-struck personality with her.
Despite her promise of never forgiving him, she was happy when he saved her from hitting the ground after his sister freed her from Smoothie's grasp and referred to him as “Sanji-Kun” again. When he returned to the crew officially, Nami (along with Brook and Chopper) gave Sanji a tight hug with tears in her eyes, causing Sanji to get excited and flip out, which caused Nami to evade him when he tried to hug her back several times. When Nami revealed she had Zeus serving her, Sanji angrily told the homie that he was Nami’s servant long before it showed up.
When Sanji met Robin, he became lovestruck with her, and he along with Luffy were the only ones who accepted her in the crew. He treats her the same way he treats Nami, though Robin always remain calm and polite towards him. When Robin told Sanji and Chopper of her intention to leave the crew because of her dark past, Sanji was a bit shocked at this revelation, but later told Chopper that there was something holding her up and a true man always forgives a woman's lies. After learning of Robin's true intentions of leaving with CP 9, Sanji became more determined to rescue her, and beated anyone who badmouthed her such as Wanze for calling her evil. After rescuing Robin, Sanji tried to hug her, before being pushed out of the way by Nami and Chopper.
During the battle against Oars in the anime, while the crew attempted the "docking" technique where they all combine, similar to a "Mecha Robot", Sanji realized if Robin performed the "docking", he could possibly see up her skirt. While thinking this, Robin shot him a sharp deadly look.
" Your eyes back then.. They were telling the truth. Even if a million of people doubted you, i will never doubt a woman's tears !"
Despite being set up, Sanji affirms his faith in Viola.
When exploring the island of Dressrosa, Sanji met a flamenco dancer named Viola who had a grudge on a certain sniper. Naturally, Sanji offers his assistance without hesitation, and becomes immediately infatuated with her beauty. Not long after that, it was revealed that Violet was one of Doflamingo's underlings, but in spite of being beaten up, Sanji believed that she was serving against her will, and still wanted to help her. She does not believe him at first, but realizes that he is being sincere after she uses her Devil fruit abilities to look into his mind. Having been touched by Sanji's sincerity and kindness, she eventually betrays her underlings and urges Sanji to leave Dressrosa, using her powers to show him that he fell into a trap. She cried and thanked Sanji for believing in her, despite her being his enemy. Later, she gives him a Den Den Mushi to warn Law, and also gives him a map to get to the hidden SAD factory.
"Pudding: I have deceived countless people like this.
Sanji: And were you one of them, Pudding-chan ?"
Sanji, asking Pudding about her twisted personality.
" The wedding was a trap.. And although everything was an act put on by Big Mom pirates... I'm glad that my fiancee was you, Pudding-chan."
Despite the cruel deception Pudding put him through, Sanji reciprocrated it with his chivalry and kindness.
In order to assassinate The Vinsmoke family and obtain their technology, Big Mom pretended to form an alliance with the family by marrying her daughter; Pudding to their 3rd son; Sanji. Following her mother's orders, Pudding agreed to take part in the plot by acting as Sanji's arranged fiancee. When she first met Sanji, she pretended to be in love with him, however, the latter rejected her, since marrying her would seperates him from his friends, which shocked Luffy and the others, who were suprised that Sanji would reject an attractive girl such as Pudding. During their second meeting, Sanji and Pudding conversated more about their marriage, where Sanji showed her his swollen face and told her of his horrible past with his family, he even accepted to marry her, as long as her mother doesn't lay a finger on his friends. Originally, Pudding thought little of Sanji and saw him as nothing more than a pawn. To add insult to the injury, when she took his sister, Reiju in custody, she revealed her third eye and her cruel personality, where she mocked Sanji; imitating his swollen face, calling ugly and unworthy of being a prince, and also revealed her mother's plan to assassinate his family, unaware that Sanji was eavesdropping on her conversation. Pudding's betrayal left Sanji heartbroken, crying silently on the rain. Eventually, Sanji reunited with Luffy and the straw hats, and formed an alliance with Gang Bege, to crash the wedding and assassinate Big Mom
Prior to the wedding, while Sanji became aware of her true nature, he struggled to keep his composure due to Pudding's beauty. When Pudding told Sanji to kiss her in the mouth, Sanji became exited, getting a rocketed nosebleed that led him crashing on the wall, while Pudding became internally disgusted with his perverted behavior.
During the wedding, Pudding was prepared to kill Sanji. During the exchange of vows, Pudding showed her third eye to Sanji, expecting a shocked reaction from him that would gives her the necessary time to shoot him. However, much to her surprise, Sanji, told her that her third eye is beautiful. Stunned by this comment, Pudding broke down in tears and couldn't bring herself to shoot Sanji since he is the first person in her life to say something nice about her third eye. Sanji's compliment made her remember her past childhood, when she had been mocked, bullied by everyone, even her own mother was creeped by her third eye, and advised her daughter to grow out bangs to hide it..After seeing her crying, Sanji realised the truth behind her cruel facade, and didn't hesitate to save her, when Luffy emerged from the wedding cake, destroying it in the process. Sanji carried her away from the scene, however after they landed, Pudding furiously attempted to shoot Sanji, but fails. Despite finally revealing her nature to Sanji; stating that she deceived countless people like him, Sanji simply asked her if she also had been deceiving and lying to herself the whole time, which caused her to tear up and waver, before being coldly slapped away by her brother Daifuku, for failing in her task. Later, Pudding witnessed Sanji's kindness once more after seeing him saving Nami from falling heroically, as she looked at them, shocked. After Bege and the Straw Hats escaped, Big Mom developped a craving for the wedding cake. Pudding volunteered to make it with the help of Chiffon, stating that she was insulted by Sanji, and wanted revenge against him. However it is revealed to be a lie, as she told Chiffon the real reason she wants her help wasn't for her mother, but to save Sanji and his friends; revealing that she had genuinely fallen in love with Sanji due to his kindness and for accepting her for who she is.
After recruiting Chiffon, Pudding decided to recruit Sanji as well, as she remembered that during their first meeting, he tought her how to make sweets. However, after seeing Sanji once again, she became infatuated and lovestruck with him, while trying to tell Sanji about their mission of making a wedding cake, she developped a split personality disorder, between loving and hating him back. She even developped respect towards him, calling him "Sanji-san" in a hilarious and interrupted way. Despite relapsing on her evil personality and speaking badly of him, Sanji pays no mind to it, and remains friendly with her, complimenting her, and even worries about her when she was wrapped on her homie carpet; Rabyian, telling her not to fall, which made her blush and lovestruck. She even became shy around him, always blushing while looking at him.Pudding's time around Sanji lead her to develop the same personality as Sanji's, as she always gets excited and nosebleeds whenever Sanji does something amazing such as complimenting her chef outfit, kicking her brother Oven aside, making a special ingredient that makes a chef faint over its sweetness, and lifting the carriage that carries the chefs and the cake with a single kick. She also developped an admiration for Sanji's cooking skills and his pride as a cook, when the latter convinced Bege not to sabotage the wedding cake, since his pride as a cook is to feed anyone who feels hungry. After finishing the wedding cake, Pudding took Sanji back to his friends and later back to rescue his friend, Luffy. Sanji thanked Pudding for her help, while Pudding told Sanji while blushing that she wanted to avoid being mistaken for a couple.
While waiting for Luffy, Sanji decided to part ways with Pudding once Luffy returns back. Sanji thanked her sincerely for her help, but Pudding rejected it, telling him in her mind that she was the one who deceived him and tried to kill him, and that she is the one who should be thankful and apologise for everything she did. Seeing Pudding confused, Sanji remembered his time with Pudding, telling her despite being enemies, and everything that happened between them up until now, neverthless, Sanji told Pudding that he is glad that she was his fiancee, which left Pudding in tears, touched by his kindhearted words once again. Pudding asked Sanji for a last request, throwing his cigarette away. She kissed him, affectionally calling him "Jiji" and thanking him for everthing, before saying goodbye. Sanji was overjoyed by that as he became lovestruck. However, Pudding used her devil fruit's ability to erase sanji's memory of the kiss, leaving him unaware of her last request, before going away from him. When Big mom's cravings stopped, the citizens praised Pudding, but she honestly admitted that the credit didn't belong to her.
After Sanji and the straw hats escaped, Pudding sat in an alley; remembering the moments she spent with Sanji while treasuring the memory of the kiss. Sanji's departure left Pudding very devastated and deeply heartbroken, as she continued to cry while thinking about Sanji.