cross my heart保证、发誓

And I won't tell any of the other girls anything you tell me about it. I promise, cross my heart.

我不会把你告诉我的事告诉任何其他女孩。我发誓，保证不会。

《柯林斯高阶英汉双解学习词典》

Carol: Mom, it's just between us, cross my heart.

卡罗尔：妈妈，这是你我之间的秘密，我保证。

Honey, cross my heart, I’ve never looked at another woman since the first day I set eyes on you! Believe me, that’s the truth!亲爱的,我向你发誓,自从我见到你以来,我就没看过别的女人一眼。相信我,这可是千真万确呀！

所以，爱上你心爱的人，就一定要大胆地表白，最好用上这个时髦的短语：cross my heart保证、发誓

cross my heart是“发誓”还是“穿越我的心”