Confident
/ˈkɒn.fɪ.dənt/
noun
A person in whom one can confide or share one's secrets: a friend.
adjective
Very sure of something; positive.
“I'm pretty confident that she's not lying, she's acting normally.”
Self-assured, self-reliant, sure of oneself.
(in negative sense) Forward, impudent.
Synonyms: self-assured