Isobel had to pick her wording carefully. She didn't want it, but if she acted like she didn't, he might catch on to the fact that she had feelings about some things. Feelings about him. But telling him he wanted it wouldn't be good either, it'd probably piss him off or make him think that she was somehow behind it. She didn't want to torture him. Just to let him move on.
"No, I didn't," she answered with a shrug, "but the great thing about being what I am is that it allows me to not care."