I trust myself quite a bit. I wouldn't be me, or be able to function if I didn't.
It is because I have a very high degree of self control, and I never cross it willingly unless I know the outcome (and if it is worth it or not). I have to remain in control of myself and to an extent my environment. If I have this, it fosters trust, therefore I trust myself. I know myself well, so I know what I can and can not do, and what I will like do in certain circumstances. Situations where I know something would go awry, or I know I would mess up, I will not do. It is that idea that makes me trust myself. As I will avoid things that would mess something up. Of course, it doesn't go so far that I become cocky. This process is active, not passive, so I always pratice it and it doesn't become automatic, which could lead to a problem