Na-adjective (keiyodoshi), Noun which may take the genitive case particle 'no', Taru adjective, Adverb taking the 'to' particle
full of confidence; brimming with (self-)confidence; having great faith in oneself
彼は勝てると自信満々だ。He flatters himself he will win.
Also written 自信満満【じしんまんまん】