- assurance, self-assurance, confidence, self-confidence, authority, sureness - freedom from doubt; belief in yourself and your abilities; "his assurance in his superiority did not make him popular"; "after that failure he lost his confidence"; "she spoke with authority"
--1 is a kind of certainty
- sureness - the quality of being steady and unfailing; "sureness of hand"
--2 is a kind of steadiness, firmness