self-possession
/ˌself-pə-ˈze-shən/
noun
control of one's emotions or reactions especially when under stress : presence of mind, composure
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. assurance carries a stronger implication of certainty and may suggest arrogance or lack of objectivity in assessing one's own powers.