Reverend Simon Simpless writes to Amelia, telling her that she can trust Juliet. He says that she's stubborn but even as a child, had a shocking amount of integrity. Her parents died when she was twelve and Juliet went to live with Dr. Roderick Ashton. He, unfortunately, had no sense of humor and no imagination, which is why Juliet ran away. Reverend Simpless suggested a boarding school and there, Juliet thrived. She became friends with Sophie and Sidney and that helped immensely. Reverend Simpless closes by saying that Juliet is extremely trustworthy.
In contrast to Bella's letter, Reverend Simpless shows that he values non-familial relationships and believes they can save a person's life. His reasoning for why Juliet ran away also indicates that children require someone to meet them on their level in order to trust them, something that Dr. Ashton wasn't able to do.