Doubt is a mental state in which the mind remains suspended between two or more contradictory propositions, and is uncertain about them. Doubt on an emotional level is indecision between belief and disbelief. It may involve uncertainty, distrust or lack of conviction on certain facts, actions, motives, or decisions. Doubt can result in delaying or rejecting relevant action out of concern for mistakes or missed opportunities.

Distrust is a formal way of not trusting any one party too much in a situation of grave risk or deep doubt. It is commonly expressed in civics as a division or balance of powers, or in politics as means of validating treaty terms. Systems based on distrust simply divide the responsibility so that checks and balances can operate. The phrase "trust, but verify" refers specifically to distrust.