I think you're reading a bit too much into it if you interpreted it as the teacher instigating him to assault her. I think she was just telling him to try to become her boyfriend and to be proactive about it. That being said, I did immediately feel like the whole teacher interaction felt very off, because there's no fucking way a teacher would try to get this involved in the love lives of her students in the first place, and I think it's pretty rare that they would get this involved even when they ought to (like if there's a bullying situation). Like "OH NO, A POPULAR HIGH SCHOOL GIRL ONLY HAS GIRL FRIENDS AND DOESN'T LIKE BOYS, THIS IS CLEARLY A SERIOUS PROBLEM THAT REQUIRES TEACHER INTERVENTION". Bro, plz. It's a pretty severe case of bending the laws of probability in order to orchestrate a wish fulfilment fantasy for some sad, lonely nerd.