To be an investor you must be a believer in a better tomorrow.

The line frames investing as an essentially forward-looking act: you commit capital today because you expect productive enterprise, innovation, and economic life to yield greater value in the future. It also implies a psychological requirement—patience and resilience—since markets fluctuate and returns are rarely immediate. In Graham’s value-investing tradition, “belief” is not blind optimism but a disciplined confidence grounded in analysis: buying assets with a margin of safety and holding through volatility presumes that, over time, underlying business value can assert itself. The quote thus links rational appraisal with a temperamental readiness to endure uncertainty in pursuit of long-term improvement.