eat one's hat
Definition from Wiktionary, the free dictionary
- (idiomatic) Used in a result clause to express disbelief in a proposition expressed in a conditional clause.
- If England signs into the European single currency before 2020, I'll eat my hat.
- He said he would eat his hat if more than ten people came. He'd better fetch a knife and fork!
to express disbelief about a proposition
Persian: من كلاهم را ميخورم