How could Esther feel responsible for Mr. Boythorn's sadness? In addition, what does this imply about Esther?

Esther knows that her aunt left Boythorn in order to raise her when Esther was a baby, thus breaking his heart. Esther is far too sympathetic, guilty and overly-caring about people, illustrated by her own portrayal of herself. She is self-effacing, humble and pure. In fact, she is much too good to be realistic but she is Dickens' way of telling us that good will always win out. She tries hard to help Richard and is admired by the other respectable and kind character in the story, Mr. Jarndyce.