confidence

Etymology

From Middle English confidence, from Latin cōnfīdentia (possibly via Old French confidence), from cōnfīdō (“believe, confide in”) from con- (“with”) + fīdō (“trust”). Morphologically confide + -ence.

noun

1. Self-assurance.
2. A feeling of certainty; firm trust or belief; faith.
   I tell you this in the strictest confidence.
   Khedron hesitated for a moment, wondering how far he should take Jeserac into his confidence. He knew that Jeserac was kindly and well-intentioned, but he also knew that he must be bound by the same taboos that controlled everyone on Diaspar. 1956, Arthur C. Clarke, The City and the Stars, page 39
   But electric vehicles and the batteries that made them run became ensnared in corporate scandals, fraud, and monopolistic corruption that shook the confidence of the nation and inspired automotive upstarts. 2006, Edwin Black, chapter 1, in Internal Combustion
3. Information held in secret; a piece of information shared but to thence be kept in secret.
4. (dated) Boldness; presumption.