If you think you can do it, you can.

The line expresses a compact, motivational claim about self-belief as a prerequisite for achievement: conviction can unlock effort, persistence, and the willingness to attempt difficult tasks. Read charitably, it is less a literal guarantee of success than a statement about psychological conditions—if you believe an action is possible for you, you are more likely to take the steps that make it possible. It also implies the opposite: disbelief can become self-fulfilling by discouraging action. As a quotation, it functions as an aphorism of agency, emphasizing mindset as a catalyst rather than external circumstance as the sole determinant.