cross one's heart
我保证
A:Jenny, what's wrong with you? Why do you keep weeping like that?
A:珍妮,你怎么了?为什么一直哭?
B:Mary told me that she had seen you with Joan last night. I got to know the fact that you are playing the field.
B:玛丽说她昨晚看到你跟琼约会,我终于知道你是个花心大萝卜了。
A: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.
A:宝贝儿,我向你发誓,自从我见到你以后,我就再也没有对别的女人多看过一眼,这可是千真万确的呀!