confidentHe was confident that his approach would work best.
assuredShe gave an assured performance to a packed concert hall.
self-assuredThe interview showed her as a very self-assured woman.
self-confidentHe was self-confident and sure he'd get the job.
assertiveYou'll have to be more assertive if you want to be promoted.
boldHe was a bold and defiant little boy.
be sure of yourselfHe seems very sure of himself.
brashdisapprovingShe's a brash know-it-all.