I believe confidence has everything to do with your willingness to try things that you might fail. You have to be confident that failure will not ruin you, and confident that you'll learn from your failures, and confident that the learning will lead to eventual success.

Self-esteem means believing (and having confidence) in your own abilities. That doesn't mean you people should say "you are great" for trying, but people can say "trying is useful" on the path to accomplishing what you set out to do.