Whenever you say I believe in myself, have you ever observed the situation? Is it a doubtful situation? a doubt on your own capabilities? You are indeed doubting yourself and so talking about believing. The reason being what we know we don’t need to believe that. The belief is required only when we don’t know something. For e.g. I believe that there are infinite universes, I believe that there is a/ there is no god, I believe I can do it etc. Believe is word behind which there is a confusion and doubt and so to make ourselves feel better we use the word I believe in myself. Just accept what you know and what you don’t know and then move forward to acquire the knowledge which you don’t know. Enforcing and chanting the words to yourself will do more damage than good. You may feel good for a short period but ultimately it would not be fruitful.
So next time, try this – when a need arises and you say I believe in myself, just observe the situation. Observe your heartbeat, your body temperature, your mind fog and your willingness to learn the skill which lead you to say the words. You will come to know yourself better.