“An engaged woman is always more agreeable than a disengaged. She is satisfied with herself. Her cares are over, and she may exert all her powers of pleasing without suspicion. All is safe with a lady engaged; no harm can be done” – Mansfield Park, Jane Austen.
But once the engagement be broken?

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The girl must have lost her wits – had lost them, indeed. That was proven, by her rejection of such an excellent, undeservedly excellent parti as Edmund Bertram. Mrs Norris nodded to herself decisively, the fresh brisk breeze blowing colour into her pendulous cheeks. – Three Letters & A Broken Engagement (Volume 1 of Oh, Fanny!: A Mansfield Park Variation by Alex Ankarr.