Near the end of the film, Christof compares the real world with his “manufactured” world. What reason does he use to convince Truman to stay in his manufactured world?

Christof tries to keep Truman from leaving by telling how horrible things are on the other side.... warning him that horrors are to be found on the other side of the wall. Truman, however, doesn't care.... he wants to satiate his curiosity and explore. He wants to experience the unexpected and the unexplainable.