Meaning of CONFIDENCE in English
1》 the belief that one can have faith in or rely on someone or something.
↘a positive feeling arising from an appreciation of one's own abilities; self-assurance.
2》 the telling of private matters or secrets with mutual trust.
↘a secret or private matter told to someone under a condition of trust.
in someone's ~ in a position of trust with someone.
take someone into one's ~ tell someone one's secrets.
ME: from L. confidentia , from confidere (see confident ).
Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004