No, this isn't a question about who Henry and Emma are :-) Just a thought that crossed my mind while reading.

The comparision JA does between Anne and Emma displays just how good a person Anne is. While CW's request isn't nearly as "cruel" as Henry's, he is asking his former love to take care of the woman she perceives to be his new one. That she actually agrees and seems to want to do it is a true testament to her love for him. She wants to help because it's the right thing to do, and she is capable of doing it. But, more than that, she's willing to endeavor in making his life easier in any way she can. If nursing the woman he now loves back to health brings him peace and happiness, then she'll do it. For him. /I could cry/

Self-sacrificing love is at times painful, and Anne doesn't hesitate for a moment. His needing her must have affected her greatly. JA had said that Anne was "almost too good for her," and this passage demonstrates Anne's goodness perfectly.