So
@botodopo while I get where you're coming from, there's a few points that a lot of people are seeing that make the situation different to them. First of all is intent, the in the 1st story the guy intended to
hurt the woman he loved in order to change her behavior, in this story the girl genuinely believed the prince was indifferent and it was actually highlighted before she made her plan that she tried to understand him but couldn't and came to the assumption he was putting on a fake smile to go along with an engagement that he didn't want, so she was trying to give him the opportunity to be with someone he loved albeit she went through it in a big of a childish way prompted by her story. A second part of things deals with knowledge, in the first story the guy already knew that she loved him meaning that he knew his actions would actively harm her, while in this story as stated all her interactions with him had lead her to believe that he didn't care for her so she thought that while he'd be disgusted that it wouldn't emotionally hurt him something with the guy in the first story actively knew. Now, if we were talking about things from a more 'legal' standpoint and just observing the actions taken I can understand where you're coming from (as the actions the guy in the first story and the MC in this story took certainly are comparable even if not exactly the same), but the people in the comments section aren't looking to enforce a divorce or send people to jail or something so the emotional component that we're afforded as the audience of a story rather than a jury unable to see what people are thinking, is going to play greatly in how people respond to the stories emotionally.
Should the MC in this story have actually talked things out with the guy and worked out an agreement where they would work together to fake a reason to break off their engagement that would suit both of their families so that they could pursue actual love (which the Prince wouldn't have agreed to, but the MC believed that he didn't love her so that would have been a reasonable action for her to try to pursue)?
Yes, but a lot of stories are born out of flawed characters making flawed decisions, the MC in this story is portrayed as a kind of 'high int low wis' character, where she is able to think things through logically but fumbles in the application (this is demonstrated for example by how she spent so much time trying to become the perfect vilalaness only to realize too late that she didn't know how to actually bully someone and had to think things up on the spot) and because of this it's not out of character for her to jump the gun and think that if the Prince is willing to annul their engagement because she bullied someone that he must truly love her and things would work out, I don't fault you for not liking the character but she is consistent as she is shown to be naive where it matters most. With the Prince in the first story though we know that he actively loved the MC, knew her feelings, wanted her to confess, and was aware of the emotional baggage in the way and wanted to help her get over that, so he... Acted in a way that he knew would hurt her in one of the worst ways possible to hope that when at her lowest she'd be able to step up to the challenge rather than crumble under the anxiety/pressure and be unable to speak at the time? In the first story, the guy knowing her feelings, knowing her baggage, loving her, wanting what he believes is best for her, and being smart enough to plan a convincing enough fake annulment that would convince at least the two people directly involved that it was real along with the patience to pretend to be someone else to pull it off is inconsistent as someone that smart and patient while that aware of the MC's true feelings and problems would have no reason to not talk it out with her making his character inconsistent.