to think (i.e. to take it to be true that ...) (Usually there is an implication that the notion is mistaken &ndash / except when expressing one's own current opinion.)
lit. to wash one's heart and renew one's face (idiom) / to repent sincerely and mend one's mistaken ways / to turn over a new leaf
大错特错
dà cuò tè cuò
to be gravely mistaken (idiom)
郢书燕说
Yǐng shū Yān shuō
lit. Ying writes a letter and Yan reads it / fig. to misinterpret the original meaning / to pile up errors / refers to the letter from capital 郢[Ying3] of 楚[Chu3] in which the inadvertent words "hold up the candle" are mistaken by the minister of 燕[Yan1] as "promote the wise"
革面洗心
gé miàn xǐ xīn
lit. to renew one's face and wash one's heart (idiom) / to repent sincerely and mend one's mistaken ways / to turn over a new leaf
chà