I'm going after a girl who rejected me until the point where the school intervened
That's very intense. Do you still plan to go after her after she's already rejected you?
If I don't, I will try to make her rejection as cruel as possible by talking s*** about her.
You should not try to attack someone for not wanting to be your friend. This is a waste of precious energy.
I can't help it, she's a b**** and she can't get laid.
That's entirely her business and you don't have a say in anything she does and it is her right to not want you as a friend or a boyfriend, so you better respect that. Find someone else that will be interested with you so that you don't end up being miserable and try to be happier.