In part 2 of The Book Thief, Liseal takes some of the wshing money to send her letters to her real mother. Why does she punish herself?

Liesel continues to write to her mother because she still has hope. In Part II, we learn that Liesel began writing letters to her mother and checks the mail daily expecting an answer, but she does not receive a response from her mother. Liesel writes several more letters to her mother, but doesn't send them. Rosa loses another customer. On Liesel's birthday she receives no presents, but resolves to take some of the scant ironing money to mail her letters. When Liesel admits to stealing the money, Rosa starts beating her but immediately stops and apologizes when Liesel says that she mailed her letters. Liesel realizes that she will never see her mother again and remains on the kitchen floor, unable to move. She sheds a single yellow tear.