A friend should always underestimate your virtues and an enemy overestimate your faults

Santino, never let anyone outside the family know what you are thinking. Never let them know what you have under your fingernails. I think your brain is going soft from all that comedy you play with that young girl. Stop it and pay attention to business. Now get out of my sight.

Any man can turn traitor.

Actions defined a man; words were a fart in the wind

In Sicily, women are more dangerous than shotguns.

And in that fraction of a second before anything actually happened, Santino Corleone knew he was a dead man.

Tell my father I wish to be his son.