Doctor: Clara, be my pal. Tell me, am I a good man?
Clara: I… don’t know.
I took this from the preview clip for Into the Dalek. So I don’t know the exact context yet. But I can guess. Certainly, the Doctor has good intentions but that doesn’t make a person good. People with good intentions can end up doing terrible things.
BTW, I like the look of exasperation the Doctor has at not knowing the answer.