It's not that she doesn't like her personally. It's because of Elenora's family. In the beginning, they explained that there are two sides of nobles: the ones who support current royalty and the ones who don't. Elenora's family is kinda an important family on the side of nobles who want to overthrow the current king. So she wants nothing to do with her since she doesn't want the royal family to think suspiciously of her.
Thanks to jinchan,
Another soon to be cute couple