Your chances of success in any undertaking can always be measured by your belief in yourself.

Collier’s line expresses a core tenet of early twentieth-century self-help: that inner conviction is a practical predictor of outward results. “Measured by your belief in yourself” frames self-belief not as vague optimism but as a kind of internal yardstick—if you approach a task expecting failure, you are less likely to persist, take risks, or recover from setbacks; if you expect you can succeed, you tend to act with greater initiative and resilience. The quote also implies a feedback loop: belief shapes behavior (effort, consistency, learning), which in turn shapes outcomes, reinforcing belief. It is motivational, but it also cautions that undermining self-trust can quietly cap one’s performance before external obstacles do.