confidence (n.)youdaoicibaDictYouDict[confidence 词源字典]
early 15c., from Middle French confidence or directly from Latin confidentia, from confidentem (nominative confidens) "firmly trusting, bold," present participle of confidere "to have full trust or reliance," from com-, intensive prefix (see com-), + fidere "to trust" (see faith). For sense of "swindle" see con (adj.).[confidence etymology, confidence origin, 英语词源]