"I like you!"
When Severus Snape heard this confession, he was filled with disgust. He didn't believe that anyone in the world would pursue him, let alone a pure-blood lady. This was probably some kind of trick.
Later, I don't know when, when he fell in love with Rose, he began to worry that she gave up on him because of her rude rejection last time, or because he poured cold water on her again and again when she pursued him.
~~
In fact, the reason why Rose confessed to Snape, who was gloomy and difficult to get along with, at first was because she didn't want the Foley family to fall into the hands of other pure-blood families, so she had to find a mixed-blood to marry. Only mixed-bloods could get married, right?
Besides, she likes Senior Snape's sarcastic tone. It's so cute!
Purpose: Wish for world peace