What does the author intend to suggest

about the housekeeper by writing that

"her throat seemed lined with fur"?.

It refers to the personality of the landlady, from this phrase you get a feeling that it is related to an animal, but with the full context, it complements the sense that the landlady is hardhearted. I get the sense that this woman says what she needs to say to get her living and rent her rooms to whoever she can. Fur is something we relate with animals, but also something we relate with warmth and coziness.