After reading the story, I find the girl a careless person. If I were in her situation, I would feel very embarrassed, too. I have learned from the story that we shouldn't accuse anybody of anything we are not sure of. I think she might feel embarrassed because that was not her money. Perhaps the girl could place a notice in a local newspaper to apologize to the boy and contact him to give the money back, or maybe she could get on the same bus next day and look for the boy to return him the money.