I don't think about confidence much. I think at some point in time confidence is replaced, at least a little, with wisdom. I am confident in my abilities to complete my day to day activities maybe because I have a routine that I have honed to a sharp edge. I am also confident in my passion for writing. What are you confident about?
What I am not confident about is truly capturing an experience with all the bells and whistles of emotions and thoughts on paper. Don't get me wrong, I can write and develop situations with emotions and thoughts but does it really capture what I'm after? This is the question I ask often. Perhaps this is part of the joy and lure of writing outside of our experiences. If I write about something I must research then capturing the thoughts and emotions of the characters can be determined by me at that time. Writing about something I have experienced firsthand though can be tricky.
There have been times when things simply would not come together or perhaps I was just a little too critical on my writing at the time. I find myself thinking things like, that didn't happen like that or no, that doesn't capture just how upset he was. Thoughts like these drive me crazy but it is part of writing. What do I do in situations like this? Most of the time I leave it alone and continue writing until it is time for a second reading. If I am being too critical then the second time I read it all will sound correct. However, if it is truly out of line then I will re-examine it to find out why.
No one can really tell you if you capture a scene correctly because, just like history, it is told from the eye of the beholder. However, you will know when you are close to how you perceived it when it really happened. Trusting your feelings and abilities builds confidence; that I am confident about.