self-assurance
1. [ noun ] freedom from doubt; belief in yourself and your abilities
Synonyms: confidence assurance self-confidence authority sureness
Examples:

"his assurance in his superiority did not make him popular" "after that failure he lost his confidence" "she spoke with authority"

Related terms: certainty certain uncertain
Similar spelling:   self-assured
  self-service
  self-assertive
  self-assertion
  self-asserting