Jim thinks that if he brings the story he heard to tell everyone he is, of course, is not just anyone. Because he is just a young boy at the age of 17 years, the chance to participate in this plan.
Jim thought he heard the story he told everyone. Surely no one would believe him Because he was only 17 years old who accidentally involved in this plan.
Jim think if he brought what he heard to tell everybody, nobody would believe him, because he is just a young age 17 years. That was a part of this plan.