The story
A conventional shortening of a wish May God bless (your/her/his/etc) heart.
Etymology from Wiktionary, CC BY-SA 4.0.
bless someone's heart
Today it means: Used to express gratitude. (Compare bless you, God bless you.) Full definition →
Today it means: Used to express gratitude. (Compare bless you, God bless you.) Full definition →
A conventional shortening of a wish May God bless (your/her/his/etc) heart.
Etymology from Wiktionary, CC BY-SA 4.0.