His patience may be short, but he seems like the sort of person to attack a problem from as many angles as possible, even when that "problem" is "trying to teach Cass", which is something Barbara - for all her intelligence and skill - always failed at.

He has a kind smile, and that makes Cass more confident in her initial opinion of him, that he's a good (if confused and new) person. That's always a relief, though she very rarely pegs people incorrectly.

She tilts her head a little, taking in his tone, expression, body language as he responds. "You... like learning."