Fateful creative solution

One unfortunate merchant owed a large sum of money to a moneylender.
The old, ugly moneylender proposed that he would forget the debt
if he could marry the merchant’s daughter.

Both the merchant and his daughter refused the proposal.
So the cunning moneylender proposed that they let Providence decide the matter.
He told them that he would put a black pebble and a white pebble into an empty
moneybag and then the girl would have to pick out one of the pebbles.
If she chose the black pebble she would become his wife and her father’s
debt would be cancelled. If she chose the white pebble she would stay with her father and the debt would still be cancelled. If she refused to pick a pebble, the merchant would have to go to jail.

Reluctantly both the merchant and his daughter agreed.
They were standing on a pebble strewn path in the merchant’s garden.
The moneylender bent over and picked up two pebbles. The sharp-eyed girl noticed that he had picked up two black pebbles and put them into the bag. Then the insidious moneylender asked the girl to pick out the pebble that was to decide her fate and that of her father.

From Lateral Thinking by Edward DeBono (1967).

Suddenly she had a brilliant idea and realized,
she’d won.
What was her solution?