When someone says they cross their heart it means that they emphasise something that is true.
Said to show what you have just said or promised is completely true or sincere.
- It means what you’re saying is true.
1. I didn’t steal money from your wallet, cross my heart!
2. I’ve been coming into work on time, cross my heart!
3. I love you, cross my heart.
4. I will move to Europe for study fashion one day, cross my heart.
acknowledge, admit, affirm, allow, assert, aver, avouch, concede, confess, declare, grant, maintain, proclaim, swear