He interprets her invitation more as a request and so he starts to run his hands through her fur. It is soothing.

"Anyone is trustworthy up to a point. I just try to make sure that point is far away."

That sounded better in his head. He tries to always be trustworthy - except when he can't be.

"No. Thank you." He knocks on the TARDIS panel with his free hand. "I've got everything I need right here."

He frowns as he thinks about what she said. "Wait, you mean here people don't trust you because you're a shape-shifter? Why?"

Because he's the Doctor so he Doctors. He's pretty bad at accepting help.