adjective
confident
KAHN-fih-dunt/ˈkɑːnfɪdənt/
Sure of one's abilities or of a favorable outcome.
The confident woman stands composed at the lectern as she addresses her audience.

Etymology
With con- perhaps strengthening “trust,” confident expresses firm trust or assurance. In the selected sense, that trust is directed toward one's own abilities or toward a successful outcome.
In context
We then need to review this, check it for errors, make sure we're confident in it, draft it into a letter of offer, and submit it to our client.
More examples
- We are confident that the repairs will last.
- Practice makes him more confident behind the wheel.
- Her confident smile reassures the nervous players.
Forms
confident · more confident · most confident
confidence noun — Trust in one's abilities or likely success.
confidently adverb — With assurance in one's abilities or expectations.