Two sisters walked up to a house. They were dressed in dirty clothes and looked starving. They knocked on the door, and when it was answered, the elder sister spoke.

"We are in need of money. My name is Ella, and this is my little sister Sarah," she said, gesturing to the other girl. "Our mother died giving birth to me, and our father died recently due to an illness. We are starving. Would you be so kind as to give us some money?" Ella said.

The lady who answered the door thought for a moment, then answered, "You are a liar. I will not lend you any money."

Why does she think the sisters are lying?