Help me please.I told her my past, she says she cant ignore it, she wants to leave me?

So here i go.I started my quit program 4 month ago.(yeah...i was addicted).i met this girl about 3 month ago and i really fell for her.in the first days, she told me i behave suspicious, and she thinks that i have a problem. i knew that no one believes you when you say i am in the quitting program so, i told her everything is OK.our relationship goes very well and i asked her to marry me.my problem was almost solved and i was in the last days of taking medicine. she had problem with my smoking and she had been asking me to quit smoking before our marriage. she took me to an institute for getting a council. the CONSULTANT took me an urine test for nicotine, but it was a trap. my test showed them there is opioid in it and it proofs that i am an addicted. i knew why it was like that, it was because of my previous day treatment,my program medicine.i told her the truth, i told her i am in my last quitting day.she did not believe me.this is 2 days that i have cut all my treatment and i feel great, i really did quit.i really feel great about what i have done on my own,it was never easy. but this girl, can not believe these coincidence. i understand her. she worries for her life.but i really love her.What should i do? How can i make her believe it was the truth and nothing but the truth?