I cannot disagree the relationship comes off very naturally but I think that this is because Henry naturally assesses people almost without thinking about it. Because he is so naturally witty and clever, it is done without design through general conversation no matter whether male or female, young or old. When Henry and Catherine are introduced, I think he sees her as he might his sister Eleanor, or possibly an amusing acquaintance with whom he wouldn't mind passing some time with or engaging in a dance with at balls. Their first conversation where he mocks the cliches of Bath and its activities and women's diaries tells him how green she is but also that she can have opinions despite her naivete. He sees that she is eager to improve herself and takes on the role to help her but as the attraction unexpectedly develops, these tests and quizzes take on the added benefit of helping him to gage her character and compatibility which I believe is really important to him in choosing a life-long partner. No, I'm not saying he thought he'd better question her to see if she fit the bill. Actually, I don't think he has been on the 'look-out' for a wife at all, but I think he has most likely long ago come to some decision of what he wants in one.