We all have doubts sometimes, that could be triggered by so many different outside factors, especially when we deal with rejection. We often ask ourselves, "Am I good enough?" or "Am I beautiful enough?" or anything of the like. The truth is that we are all good enough, and beautiful enough, etc., but the truth is that many people may not see it that way. If someone has dealt with rejection multiple times throughout their lives, they could easily start believing the opposite. And it turn, that could translate in feeling as if you have to prove yourself, when in reality you don't. As a result, you could also see yourself feeling undeserving, when again, that is just a perception based on a thought that you had as a result of your circumstances. But circumstances can change.
The good things about this, however, is that like all things, beliefs change. The moment you start you incorporate good and positive thoughts about yourself, the moment your mind starts to change and your subconscious works in a way that you actually start to believe the positive thought.
Some of positive affirmations that you could incorporate into your daily practice are:
I am good enough
I am beautiful enough
I am strong enough
I capable enough
These are only some of the affirmations but they could go a long way if you apply them daily.