[Daivia]

I think the best way to prove it to her is to not let your anger get the best of you again. Learn some new coping mechanisms- don't let yourself get so upset that you lose control.

The only way to prove it to her is to keep it together for the rest of the time you are together. You can't just say you've changed, you have to live it. And live with the consequences if (when) you mess up.