In ch.30, we are told that "[Henry's] affection originated in nothing better than gratitude, or, in other words, that a persuasion of [Catherine's] partiality for him had been the only cause of giving her a serious thought."

I had noticed before I started reading the novel, that the Norton Critical Edition of NA contains a section from "A Father's Legacy to His Daughters" (1774) by Dr. John Gregory, which Julie W. provided us with during a GR of P&P. (I've linked it below - watch out for those old-fashioned esses! ;-)

JA continued on with: "It is a new circumstance in romance, I acknowledge, and dreadfully derogatory of an heroine’s dignity; but if it be as new in common life, the credit of a wild imagination will at least be all my own."

No wonder she felt the need to "apologize" for this development, because if you read Dr. Gregory's excerpt, the common idea in their time was that a woman's love could only be the result of gratitude for *the man's* love, a reaction, not an action. In her other novels, I couldn't quite make out whether JA agreed or disagreed, because it seemed to me that she both subscribed to this belief and subtly chuckled at it too.