Why wouldn't he? The ml has done nothing but manipulate Yujin from the start. He blackmailed and threatened him into marriage, using his son both as bait and collateral, while also abusing him via pheromones and forcing him into sex. You'd have to be an utter fool to think he has done anything even remotely trustworthy. He's only being nice now because he thinks Yujin has nowhere else to go and is properly chained both by his marriage status and his son. Abusers always seem so nice when you play into their hands and ml is no different. It's when you wake and take a good look at their behavior that things get rough, and Yujin is in for a hard time.
i never said he was trustworthy till this day the ml is still shit but after hearing all the stories about the dad would you still not stop and think for a sec .that just my pov however i see your point
Ok mc why believe him