I told him I was going to betray you, and betray Lyra, and he believed me because I was corrupt and

I told him I was going to betray you, and betray Lyra, and he believed me because I was corrupt and full of wickedness; he looked so deep I felt sure he'd see the truth. But I lied too well. I was lying with every nerve and fiber and everything I'd ever done...I wanted him to find no good in me, and he didn't. There is none.
----Philip Pullman, The Amber Spyglass