Read the following text and answer the question!

    Many years ago in a small Indian village, there lived a farmer who owed a sum of money to the village money lender. The money lender, who was old and ugly, love the farmer's beautiful daughter. He wanted to marry her. 

   The money lender told them he would put a small black stone and a white stone into an empty money bag. Then the girl would have to pick one stone from the bag. If she picked the black stone, she would become, his wife and his father's debt would be forgiven. If she picked the white stone, she need no marry him and her father's debt would still be forgiven. If she refused to pick a stone, her father would be thrown into the jail.

    The next day, they were on the farmer's garden. The moneylender bent over to pick up two stones. As he picked them up, the sharp-eyed girl noticed that he had picked up two black stones and put them into bag. Then he asked the girl to pick one of the stones from the bag. 

    The girl put her hand into the bag and took a stone. Without looking at it, she fell it down among other white and black stones. 

    "Oh, how clumsky of me!" She said, "But never mind, if you look into the bag for the one that is left, you will be able to tell which stone I picked."

    The money lender didn't dare to take the other stones as he didn't want other people knew his dishonesty. Finally the girl was free and the farmer didn't need to give the money back. 

What can we learn from the text?