confidant

noun

1. A person in whom one can confide or share one's secrets: a friend.

   “Heaven made you love me for no other end, / But to become my confidant and friend: / As such, I keep no secret from your sight, […]”

   “One in thought and purpose, linked by the necessity of combating one hostile fate, a power antagonistic ever, — a power we lived to evade, — we had no confidants save ourselves.”

   “'Of course'—implied the loyal manager, and 'Oh, of course; not a word,' assented his confidant.”

   “Bankman-Fried’s confidants were along for the ride. At his side was Caroline Ellison, Alameda’s CEO and his on-again, off-again lover.”