what pleas of hesters arouse sympathy and admiration in chillingworth?

Hester's plea to Chillingsworth is that he help pardon the man with whom she "sinned" with. She encourages Chillingworth to let go of the revenge which makes him so creepy and depressed.For his part Chillingworth can't let go of his dysfunctional hold over Dimmesdale. Hester gets so angry, she says,"Do with him as thou wilt!"

Chillingworth finds Hester's about face so intriguing that it arouses his sympathy and admiration,

"Woman, I could wellnigh pity thee!" said Roger Chillingworth, unable to restrain a thrill of admiration too; for there was a quality almost majestic in the despair which she expressed.