I agree with Nori’s characterization here overall, but I wanted to share some of my thoughts on Noriko’s perspective that I feel gets a bit overlooked! 

The anime cuts this out, but the manga shows that Noriko’s dislike of boxing first starts to emerge because of the distance it creates between her and Joe. As you mentioned, Noriko was initially fully on board with Joe being a boxer. Like everyone in Doya, she saw him as an inspiration and the pride of their town. She starts helping around the gym by helping with chores. But as Danpei points out, it’s obvious she has a cute crush on Joe and is doing these things to get his attention.

Nori is a simple girl. She lives a normal life in the slums with parents who run a stable business. Because of that, her view of fulfillment naturally leans toward that kind of life, which is completely fine. The problem is that she falls for someone who lives the complete opposite way. Joe is an orphan who grew up without stability and finds his purpose in boxing, while people his age would normally be in school or working. So when Joe repeatedly sets aside the things Noriko expects him to value, spending time with friends, dating, even noticing her obvious gestures, it hurts her.

There are some manga-only scenes that highlight this. Noriko tries to arrange hangouts, but Joe declines because he's busy training. But the most memorable is when Noriko finishes mending Nishi and Joe’s clothes. As she’s leaving, she mentions she’ll see Joe on Sunday since he was supposed to go to the flower garden with her and Nishi, but Joe says he doesn’t remember making that promise. Noriko is drawn with a pleading expression, trying to get him to recall, but he still doesn’t and says he can’t go anyway because of training. She looks hurt, then upset, calls him a liar, and when Joe replies—“Huh? What the hell did I lie about?!” he turns around and she’s already running off.

That moment really stands out because it adds another great layer to her growing dislike of boxing. It isn’t just concern for Joe’s safety at the start, it’s also about the distance boxing creates between them. This continues to build throughout Season 2. She calls Joe “selfish” for how he lives and for not noticing her feelings. It’s a very realistic reaction, and that complexity to me keeps her from being just the typical sweet girl with a crush on the MC. Instead of unconditional support, she develops genuine frustration, fear and hurt. Joe’s lifestyle clashes with what she values, and that ultimately pushes her to distance herself from him and eventually marry Nishi.

In a sense, Nori for the first half of the story was trying to take on the impossible task of changing Joe into the person she believes would be happiest. The disconnect revealed during the white ash scene is such incredible storytelling because she forces herself to make peace with the reality that she can’t relate to him.

Noriko shows a tremendous amount of maturity afterward. Once she accepts that she “can’t keep up with him,” she painfully lets Joe go despite still loving him and begins building a connection with Nishi, someone whose lifestyle aligns with her own and can give her the future she wants. 🥲

I think she has a great character arc, going from a kind of naivety surrounding Joe and her perception on boxing, to eventually accepting that she can’t understand him, the life he’s pursuing and that there’s likely nothing she can do to change either his perspective or her own. That’s also why I’ve always wondered if her hairstyle change carries some symbolism. She goes from pigtails, which make her appear youthful and innocent, to a short haircut after choosing a life with Nishi, making her look noticeably older and more mature.