You must believe in yourself if you are to become what you desire in life. Self-belief enables you to implement your ability, skills, and experience to achieve set goals. You can become great in life if you believe it as you mind is focused to the limit you set.
Self-belief enables you to see new opportunities with clarity even where others do not. You are therefore able to explore elements around that will help you accomplish your goals. It stimulates creativity and reasoning so that you approach issues without anxiety but with a clear mind. When you believe in yourself you present yourself with confidence and you are able to convince others so they can support you.
Self-belief gives you motivation and persistence to pursue your goals with a positive mind. This means you keep moving no matter the hurdles and setbacks you encounter. Failure is only a lesson to improve yourself to do things better until you get to your goal, you never quit if you believe in yourself. When you do not believe in yourself then you lack the motivation to pursue your goal.