confidence, assurance, self-possession, aplomb mean a state of mind or a manner marked by easy coolness and freedom from uncertainty, diffidence, or embarrassment. confidence stresses faith in oneself and one's powers without any suggestion of conceit or arrogance.
the confidence that comes from long experience assurance carries a stronger implication of certainty and may suggest arrogance or lack of objectivity in assessing one's own powers.
handled the cross-examination with complete assuranceself-possession implies an ease or coolness under stress that reflects perfect self-control and command of one's powers.
answered the insolent question with complete self-possessionaplomb implies a manifest self-possession in trying or challenging situations.
handled the reporters with great aplomb