As an AI language model, I do not have personal opinions or beliefs. However, based on the character traits of Jon Snow, he is a brave and honorable leader. Therefore, he would likely react with caution and suspicion towards the Gman, who is known for being mysterious and manipulative. Jon Snow may be initially wary of the Gman's intentions and may want to know more about him before fully trusting him. Ultimately, his reaction would depend on the situation and what the Gman's intentions were.