The simplest way to build self confidence is to be a person who keeps their word. Not to others but to yourself.
Do what you say you’re going to do for you.
Even if it’s as small as telling yourself, “I’m going to the gym today.”
Go!
Every time you follow through, you teach yourself that your word means something.
By keeping the promises you make to yourself, by being a man of his word to yourself, you build un-shakability.
It cuts the other way, too, because once keeping your word to yourself becomes a top value, you begin to be more selective with your words.