@uMoonlight
If you compare him to her, she is the bigger jerk and she is the one who started the whole fight instead of having a peaceful alliance with the goal of cancelling the engagement. He wasn't a jerk, unless reacting negatively to her annoying attitude is being a jerk.
You can be playful with your friends or boyfriend, I do that too, however, they are not friends, she even says at the end of this chapter that it was unfortunate(not sure if those were the exact words) to have met him. I mean, her attitude is annoying, but I have seen worse I guess.
I might be wrong here, but do you think Blackie considers him a friend?
I will say this though, maybe the prince never intended to cancel the engagement, he never did say his intentions, in which case, it would be easier to tolerate the mc for retaliating against a force that wants make her suffer.
I agree that she wasn't that big of a jerk, but a jerk nonetheless.