
Idk, I'm not satisfied with his character development just yet. It's good that he knows not to neglect her now, but the core of the problem hasn't been resolved: he doesn't see her as a person, he sees her as a girl. The reason why he treated the princess kindly is because he never saw her as a girl in the first place. He has now learned, that girls won't like him if he ignores them, but he still doesn't see her as the same kind of being as his friends. He doesn't tell her the truth, he doesn't just straight up admit what he did wrong and why.
It's why her studying abroad is such a big deal to him. A friend like the princess can follow whatever path she chooses, but if his fiance leaves him, it means he failed, because she's a girl he's in love with. He was taught from a young age, that the way you treat girls it's different and that is what separated them in the first place. His awkwardness around what girls like, his feigned stoicism and endless avoidance of anything sincere or embarrassing IS the reason why she doesn't know or love him.