She didn't really understand, not truly – she could never imagine being torn between Draco and Lucius if she were Narcissa, but intellectually Hermione thought she could see how it would be hard for Draco's mother to let go of her husband. She obviously loved Lucius a lot, for who he had been once, a long time ago. It didn't make Hermione warm to Narcissa at all but it was the truth, and she thought it might help Draco to hear it.