Pea,
The question you raised is a good one. It goes beyond the actual breaking of the addiction and into the maintenance of living your life smoke free. For some, that is much harder than actually breaking the addiction.
The trust issue for me was one of the hardest to deal with because I had 3 slips (the last one being 470+ days ago). Each time, I thought I was "in the clear" and wouldn't ever smoke again... but I did. So being able to trust myself after that was very hard. I don't think there was a specific moment in time when I said, "I trust myself!" but I DO remember the time when I knew that I would never smoke again... I bought cigarettes, with every intention of smoking them, but couldn't do it, so I destroyed them all one by one. From them on, I just KNEW that I wouldn't smoke again... but I still didn't trust myself completely because I'd had that thought that I KNEW I wouldn't smoke before... but did. So for me, it took a while. I guess, after countless times of being in situations where I could smoke, but didn't, I finally began to trust myself. BUT, I will never, ever, ever, ever, EVER let my guard down!!! I know that I am an addict and as such, I am one cigarette away from a lifetime of smoking. I still, on occasion, feel tempted... that feeling of "I could SO smoke right now!" and yet, know that I won't (the last time that happened was on my 1 year anniversary... so about 100 days ago). And I know of people who have quit for 10+ years who went back to smoking, so it is definitely possible and that you're never truly "in the clear."
But the good news is that I DO trust myself now. I trust myself to go out with smokers, to drink heavily (on semi-rare occasions), and even have cigarettes in my possession and have 100% confidence that I will not smoke them... but that feeling of true trust came very late for me.
I think the biggest factor in trusting yourself is accepting that you don't smoke. Smoking must not be an option. Once you've been in enough situations where you COULD smoke, but don't, after a while, you just start to gain a little more trust... and then a little more... until finally, you don't question yourself anymore. It's like a little baby who's learning to walk. They don't just walk and then it's done an