Sourced

• Danger breeds best on too much confidence.
  • Pierre Corneille, in Le Cid (1636)

• As is our confidence, so is our capacity.
  • William Hazlitt, in Characteristics (1823)

Unsourced

• Confidence is what you have before you understand the problem.
  • Woody Allen

• He who believes in nobody knows that he himself is not to be trusted.
  • Berthold Auerbach

• People have generally three epochs in their confidence in man. In the first they believe him to be everything that is good, and they are lavish with their friendship and confidence. In the next, they have had experience, which has smitten down their confidence, and they then have to be careful not to mistrust every one, and to put the worst construction upon everything. Later in life, they learn that the greater number of men have much more good in them than bad, and that even when there is cause to blame, there is more reason to pity than condemn; and then a spirit of confidence again awakens within them.
  • Fredrika Bremer

• If you have no confidence in self, you are twice defeated in the race of life. With confidence, you have won before you have started.
  • Marcus Tullius Cicero

• When young, we trust ourselves too much, and we trust others too little when old. Rashness is the error of youth, timid caution of age. Manhood is the isthmus between the two extremes; the ripe and fertile season of action, when alone we can hope to find the head to contrive, united with the hand to execute.
  • Charles Caleb Colton

• Never put much confidence in such as put no confidence in others.
  • Augustus Hare

• Trust him little who praises all, him less who censures all, and him least who is indifferent about all.
  • Johann Kaspar Lavater

• You meet these people who are confident all the time. They annoy me. And I wonder if it's because I'm envious or if it's because they're shallow.
  • Guy Pearce

• I have confidence in fools... self-confidence is what my friends call it.
  • Edgar Allan Poe

• Whatever distrust we may have of the sincerity of those who converse with us, we always believe they will tell us more truth than they do to others.
  • François de La Rochefoucauld

• Trust not him that hath once broken faith.
  • William Shakespeare