Responses
It’s a possibility but my Guwon is such an illiterate and brute that I think he believes wtv Teach says.
Guwon might be illiterate but he ain't stupid. His mind works just fine demonstrated by him waiting to punish yeonghyeon till there was doctor who could treat him, this tells he can think 2 steps ahead in certain situation. But you are right about him believing whatever teach tells him. That is less him being stupid and more him being stupid in love
Guwon probably suspects Jinwoo's intention to kill him because Jinwoo has tried attacking him in his sleep multiple times till now, and Guwon probably thinks that this comes from somewhere and is maybe the reason behind his suspicion. As the Hounds have not said anything to Guwon yet