@Kidawesome55
In the real world there are quite a few people who come back from 'evil' but that's entirely because most first world countries allow the comeback to happen and don't constantly feed you 'you are rewarded for being evil'
from the teachers point of view, she has likely has seen the edge lord or the delinquent turn their lives around 180.
I personally know a criminal with a body count that I would label a good person and has gotten out of crime entirely. (I make a fairly big distinction between crime on crime violence and crime on innocent bystander, to the point I don't personally see crime on crime as being a problem, it's a good outcome, but crime on innocent people ie not involved in crime is about the worst thing possible outside of extreme outliers)
the teacher in this case is viewing this from an almost exclusively peaceful first world pov, while the main character sees every opportunity to be evil, and every possible road he can take and the fact he is STILL trying to go screaming down the evil road