Advice?

Hi I'm Luka
I need everyone's help right now.
My friend Evan-lee is about to get back with her bf. He abuses her and treats her like shit but she keeps going back to him. she has even written a journal about what he did to her and still she forgives him.
I've tried to stop her but she won't listen to me.
I can't watch her destory herself again I just can't but I can't leave her.
I don't know what to do.
I've tried talking to her but as you can see on our profiles it hasn't worked.
Help me I really need some advice.
Please someone?
Luka J