I need to prove to my ex I have changed...

I used to drink sometime every night but since we split I've been out drinking once. Instead of lifting pints I've started lifting weights working out everyday trying to better myself. I've not spoke to my ex in a month but really want her to know how a feel about her. We've both done stupid things in the past due to alcohol... How can a prove this to her. I miss her soo much and love her with all my heart and soul.