Bless your heart
Mostly women in the Southern USA
To someone from outside it sounds like a compliment but it is really a polite way to say “you’re an idiot”. Can also be used at the end of a rude sentence to try to end the sentence on a “positive” note.
“Someone called saying I won a cruise and all I have to do is give them my bank information! Time for a trip!” “Oh honey, bless your heart”.