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.
Knowing can be a curse on a person's life. I'd traded in a pack of lies for a pack of truth, and I didn't know which one was heavier. Which one took the most strength to carry around? It was a ridiculous question, though, because once you know the truth, you can't ever go back and pick up your suitcase of lies. Heavier or not, the truth is yours now.
But keeping secrets is a discipline. I never use to think of myself as a good liar, but after having had some practice I had adopted the prevaricator's credo that one doesn't so much fabricate a lie as marry it. A successful lie cannot be brought into this world and capriciously abandoned; like any committed relationship it must be maintained, and with far more devotion than the truth, which carries on being carelessly true without any help. By contrast, my lie needed me as much as I needed it, and so demanded the constancy of wedlock: Till death do us part.