Nobody gains confidence by knowing everything. Confidence comes from filling holes in your mind with knowledge. You can’t do that if you always pretend to know everything. This means admitting that maybe you’re not the smartest person. The most confident person in the room might be the last person you’d expect.
Someone with fake confidence does the opposite. They pretend to know more than they do. They might be talking a lot and are very loud, they show of maybe with expensive designer clothes. Let's be honest it’s easy to confuse confidence with arrogance.
But real confidence is about actions, do your research, ask around, train, het organised, practice, figure things out. When you are feeling ready you are confident and you do no longer need to prent you are. But you have to accept that live also comes with a certain amount of unavoidable risk.
But you have to dare and when you fail you will learn why you failed and go from there.
Stop asking for approval but look for feedback instead of compliments. And honest people are willing to give you honest feedback. Take that criticism and build from there. And do not forget to track your own improvements.
Everyone, even a successful person has moments of doubt and everyone has those moments of being worried and yes everyone feels nervous sometimes.
But when you act, make decisions and look for answers on the questions that matter to you, you will demonstrate your confidence thanks to your actions and not by pretending to be a Super Hero's, as they only exist in the movies and in books.