As there is no question included with this quote, I will focus on explaining what the quote means.
This quote comes from <em>The Scarlet Letter</em> by Nathaniel Hawthorne. The quote is included in the scene where Chillingworth and Hester meet again. The two of them talk about their past relationship, and end on a relatively amicable note. However, Chillingworth asks Hester not to reveal his true identity. Hester accepts, but she is then surprised at the expression on Chillingworth's face. She worries that his smile is evidence of the fact that she has entered an agreement that does not benefit her, and that will prove to be "the ruin of [her] soul."
