She doesn't seem to show any remorse as in the scene where she calls MC to meet her at the park. There isn't any scene where she cries under the shower and she doesn't call you back to tell she is in Neverwhere. Also, when Linnae urge them to talk she is defensive, remorseless and won't apologize and in this path MC's father is the one who ordered her to be his watcher. She takes everything professionaly and says she never loved MC and won't regret doing what the templars ordered her to do.
Maybe she didn't faked the relationship and it was her way to give MC an easy opt out on that route, because obviously their relationship was a little bit tensed as you can see when you don't get the early relationship points. You've to act more cold towards her to get on her "it was just friendship" path. Acting cold isn't helpful in a relationship. What if she does love him but recognized her jobs hurts MC and their relationship way too much and with the truth about being a Templar on the table, she decided to sacrifice herself to give MC the opportunity to start new?
The lodge talk with Kaija gives us many informations about her feelings and why she acted like she did. For starters she told MC she had a crush on him since they were teens. At that point, she already knew about the Templars and what his father was. She goes on to say that her initial reaction to the Council's idea was that she was happy. It was only after a few seconds that it occurred to her that it was a bad idea. She also says that she thought that if she told MC she had never loved him and that he hated her for it, it would be easier for her to deal with the situation. Perhaps easier for MC as well. She also says that she thought it would be better to keep her distance, even if it meant lying. It seemed easier to her. She wanted to give MC a reason to move on.
The crucial point is: if MC acts coldly towards Kaija after all the revelations, she decides that it is better to just continue as friends. However, if MC is less “cold,” she reveals that she has missed him since the whole shitshow started and that she loves him. So she has loved him all along, and it is simply the cooled-off relationship, which she naturally contributed to with her lie and her behavior afterwards, that makes her decide not to continue.
What I don't understand is... so many people have already explained this in this thread. Yet I never see you acknowledging any of these points in your argument. Instead, you constantly brush aside any facts that don't fit your narrative and insist on your point of view, which simply doesn't stand up to scrutiny. You don't have to like Kaija. She's just a character in a fictional story. But you should at least acknowledge the content of the story as it is and not just rearrange it.