It can be my paranoia, but the prince is giving off an ex-husband who used the protagonist to get more power and then abandons her vibe. Like we only see MC make a big effort for the prince to gain power, like at the party and now. Why didn't he say that at the party it was all her brother's plan? like, I understand, he asked the prince not to talk, but, like, he just took advantage and gained points with the protagonist. Maybe the attack was his plan, like maybe he knew it was going to rain that day or even he was going to make another way for them to go to the cabin but he was very lucky, he knew that there was an infestation of monsters in the area, like how he wouldn't know he is a prince from a country that is dealing with them. Maybe he "protected" her because he wanted to gain MC's trustworthiness, favorability and for the MC feel guilty for that. Remembering that it's all a theory, maybe it's just my paranoia and some plot holes from the author ╮( ̄▽ ̄)╭
It was kinda refreshing... It's been a while since I read a story where I didn't predict the ending