Dedication to truth creates confidence.
A person is more than the knowledge they hold and the body they control. A person is, fundamentally, awareness of themselves. The way you see yourself changes everything about you. Thinking and feeling exactly as you are is the root of confidence. Any premise that strays from the mark of reality will color all your actions.
To act as who you are, you must know who you are. Know it more than you know anything else that you know, for self-knowledge is the root of all other knowledge. There can be no doubt. Even the slightest hesitation will seize you. Any lingering question has got to be stamped out, or you are sure to fail in any mission.
Without confidence, you are necessarily misaligned in the pursuit of your aims. You set out to try something within your reach, but you falter immediately underway. The mind keeps reaching for a new limit, but you sabotage yourself before you ever reach the edge. It takes fortitude to approach the end of your present self. Zero confidence brings you back to your comfortable center before you reach it.
Confidence is selective. Hold onto yourself in the process of realizing truth. Believe with all your mind that what is true is true because you have uncovered it to be true. The truth is nothing more or less than that. To go beyond this is pompous. You earn only certainty in your opinion when you have tested your mind against the universe.
When you are confident, you experience more of yourself because you are more active. You are empowered to do a wider range of things in the world outside you. The tools of confidence do not come from believing anything is possible, but from believing in your ability to change. The process of discovery is the source of all your power. You can restructure your physique and reshape your body. You make out the tools to channel your influence.
Before all else, make your perception match reality. It is the only way to change yourself or your environment. Anything else is self-gratifying delusion designed to bloat or destroy your power. Wherever the truth is, there you will find your place. Whatever is real is your ally. Retain accuracy as you progress through life and you will own every advantage available.