One possible plot could be that Arlong, after some self - reflection and a change of heart, tries to make amends with Nami. He could start by helping her protect her village from other threats. This would be a complete turn - around from his previous villainous self, and Nami would be initially very skeptical but gradually come to see the new Arlong.
In a fanfiction, their relationship could develop positively through shared experiences. Let's say they both get lost in a mysterious part of the ocean. They have to rely on each other to survive. Arlong uses his strength to fend off dangerous sea - monsters, and Nami uses her intelligence to find a way out. Through this, they start to see each other in a new light, and when they return, they are more open to building a positive relationship.
It works because of its complex characters and unpredictable plotlines. The diverse range of personalities and their power struggles keep viewers engaged.
Maybe Nami enjoys Story of Seasons because it offers a break from the daily hustle and allows her to immerse in a peaceful virtual world. The customization options for the farm and the progression system could also be appealing.
One Punch Man is successful as a story because it combines comedy, action, and satire. The world-building is interesting and the plot has enough depth to keep viewers hooked. The art style is distinct too, adding to its charm.
There could be many factors. Maybe she faced extreme pressure and felt she had no other choice. Or perhaps there were bad influences at work that led her down that path. It's a complex situation that requires a deeper look at her circumstances and mindset.
In some fanfiction concepts, Luffy could overhear a conversation. Maybe some of the villains are talking about their plans regarding Nami or boasting about how they've been treating her. Luffy, with his excellent hearing skills, picks up on this and figures out that Nami is in a bad situation.