We're told there are very few people who can find a fault in her, and I think Mr. Knightley, as once of those few, is concerned that now, without Miss Taylor's guidance, Emma may grow a little conceited. He says he'd like to see Emma in doubt of a return of her affections -- not that he'd like to see her heart broken. I think he believes it might do Emma some good if she had someone to please besides herself, and if she had to work a little to gain someone's affection.