From Clark's point of view, it's not so much underestimating her as it is that she gave him information he doesn't find useful or relevant at the moment. Personality can be important, but he's far more interested in what she might bring to the table in terms of what she can actually do.

"I'm not looking for anything," he says, tilting his head slightly. "Sometimes it's better to find the job that fits the person instead of the other way around."