Why was the grandma smiling at the end of "A Good Man Is Hard to Find"?
At first, the grandmother is trying to sweet talk the criminals who are murdering her family. She tries to convince them that they don't need to kill her, she wants to give them all her money, she believes that they are good people with good blood, she is trying to be charming as she attempts to save her life.
But, unfortunately, all the talking that she does has no affect on these hardened criminals. She is destined to die, and as she contemplates her fate she reaches out for God, forgiveness and eternity.
In the final moments of her life, Grandmother receives the gift of forgiveness and is graced with the hope of eternal life.