cross my heart
发誓，表示诚实或真心的意思
口语·表示发誓或真诚承诺
英文释义
to promise sincerely or to signify the truthfulness of a statement by making a solemn gesture of crossing one's chest
例句
I didn't take your cookie, cross my heart and hope to die.
典故来源
源自儿童誓言手势，用手在胸前画十字表示真诚，常与“hope to die”连用加强承诺，19世纪流行。