I never didn't trust them. I just... realized they weren't entirely relevant to our stay in Wonderland.

[That's the best way for him to put it if he wants to feel like he stopped carrying them around all the time for a good reason, not because he was scared and angry and hurt. It wasn't the journal's fault he died, and now Ford's here and so much cooler than Dipper ever imagined. He trusts the journals, and he trusts Ford.]

Besides, there's no better source on Bill, that much is sure.