What did Judith notice about Kit's feelings for William?

Judith notices that Kit has little interest in William, and that she didn't pay attention when he came to call.

"Didn't you know?" Judith threw her a condescending glance.
"Know what?"
"William came over to father's way of thinking two months ago. Even before his house was raised, when he had to pay such high taxes on his land." Now how did Judith know that? Kit stared at her. "I never heard him say a word about it."
"Maybe you just weren't listening." Judith’s tone had more than a touch of smugness.
Chagrined, Kit jerked at another dropped stitch. It was true, sometimes when William and Judith were talking about the house it was all she could do to keep her mind from wandering. But she knew she would have remembered anything as important as this. Was William ashamed to admit to her that he had turned against the King? Or did he think she was too stupid to understand?