“Mr. Knightley and Jane Fairfax!” exclaimed Emma. “Dear Mrs. Weston, how could you think of such a thing? – Mr. Knightley! – Mr. Knightley must not marry! – You would not have little Henry cut out from Donwell? – Oh! no, no, Henry must have Donwell. I cannot at all consent to Mr. Knightley’s marrying; and I am sure it is not at all likely. I am amazed that you should think of such a thing.”
– Jane Austen
Emma, Chapter 26. At the Coles’s party Emma is horrified at the idea of Mr. Knightley marrying Jane Fairfax. This is after Mrs. Weston suggests seeing a match between the two. Declaring that Mr. Knightley must not marry, Emma clutches for a reason: that his nephew Henry’s position of primary inheritor of Donwell estate would be threatened. Of course the real threat is to Emma’s as yet unacknowledged love for Knightley and desire to have him as her own. But Emma continues to deceive herself on this.