He sometimes wondered if she was simply ... incredibly in tune with him. "I was going to inquire after your sister," he murmured. "In regard to her interest in Lucius," he clarified. He knew Narcissa wasn't against him, of course, but nor was she actively supporting him.
He wondered, if she became involved with Lucius, if that would breed a potential conflict of interests, or if she would play the part of a good, pureblood wife.