I have never in my life read something so... heartwrenchingly despicable. This books literally takes you on a rollercoaster which introduces new loops as the ride goes on but still the ride is thrilling and suddenly you find yourself going to buy another ticket. I Highly recommend.
Spoliers ahead!
Personally, I feel like Verity's letter was a prevarication, an act to make her self look good if she ran away with Crew and somehow got caught. I mean everything in the book, especially the scar, kind off makes Verity's letter plausible. But then again we'll never know