cross my heart 發誓，保證
    Billy, cross my heart, it wasn’t me who broke your bicycle. 比利，不是我把你的自行车弄坏的，我发誓。
    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，我从来也没有对别的女人看过一眼。这可是千真万确的呀！