Damn I had to read that twice to figure out why that guy yelled. ( ̄∇ ̄")
He probably sees himself in the condition shes talking about. Like even though marielle alrdy said he is her type, he doesnt rlly believe her. So when she starts talking about like being forced into marriage and having no choice to reject it(even though she was talking about the price and stuff) it makes him feel like she doesnt actually want to marry him, or that she was forced to marry him unwillingly. In short he imagined himself and her inti her discussions about the price and the candidate. Which probably exploded when he heard her saying that "she might've liked someone else". So like he mad/jealous at his imagination lol
Ngl there's a couple of plot holes that are kinda sitting there but its fine. The art is pretty