When Emma muses aloud to Harriet on the subject of not getting married, she says: she has never fallen in love, she has importance and consequence as it is, she does not foresee wanting occupation or attachments in her 'old-maid-hood,' and her father's blind, consuming, dependent attachment to herself could hardly be equaled by any other.
When Mrs. Weston surmises Mr. Knightley's affection for Jane Fairfax, Emma uses very similar arguments as to why he should stay single: he is not in love with Miss Fairfax, he has occupation and interest without a wife, he does not need anything to fill up his time or his heart, and his nephew depends on the inheritance of his estate.
(And in both she manages to talk about how annoying Miss Bates is -- how sensitive she is to that, when her own father's foibles never irritate her!)