She said it as if she didn't quite believe it, but then again, he realized by now he couldn't expect her to. That just made Castiel wonder why Sam and Dean did their best to silence him when he spoke the truth. Humans heard what they wanted to hear.
And he knew what she was doing - he was aware he was uninformed, but people tended to underestimate his perceptiveness.
"There is no need to modify your behaviour, I have little interest in your personal sins," he pointed out bluntly. "I am not here to punish you."
Why everyone assumed he would smite them was another question. He generally had no interest in it outside of battle - people fearing him was just one more thing he hoped to correct once Purgatory was opened.
He nodded. "I have spoken with another woman who said the same. And a man calling himself the Doctor, though I doubt he is a certified physician."
Staring at her a little harder, he noticed something. "You are an anomaly that is not meant to exist."