Her objections to Mr. Knightley’s marrying did not in the least subside. She could see nothing but evil in it. It would be a great disappointment to Mr. John Knightley; consequently to Isabella. A real injury to the children – a most mortifying change, and material loss to them all; – a very great deduction from her father’s daily comfort – and, as to herself, she could not at all endure the idea of Jane Fairfax at Donwell Abbey. A Mrs. Knightley for them all to give way to! – No – Mr. Knightley must never marry. Little Henry must remain the heir of Donwell.
– Jane Austen
Emma, Chapter 26. This is Emma’s train of thought when she notices Mr. Knightley being “most attentive” to Jane Fairfax’s singing and piano playing. She thinks about Mrs. Weston’s suggestion of a match between Jane and Mr. Knightley and forcefully objects to it. She reaches for all kinds of reasons why the match is ill advised. But her hyperbolic dismissal of it as “nothing but evil” betrays her self-deception about her own feelings for Mr. Knightley. Her out of proportion and jealous reaction foreshadows her eventual realization that she is deeply in love with him.