IMO confidence is knowing you can make the shot. Knowing you did your homework and set up stands in the right locations. Knowing you've taken the precautions to remain scent free. Confidence will keep you on stand on a slow day when a warm shower and a beer sound better then freezing and seing nothing.

I think confidence is an important part of hunting. If you're prepared for the hunt and your ducks are in a row then you should be confident. (Second guessing yourself is a bad habit I try to avoid. I setup the way I do for one reason or another and I've found over the years that my first responce is usually the correct one.)