Erin's Questions (2)

There's this isekai webtoon wherein the female lead was sold off by her family to a king to be a part of a harem, but soon after, the king got killed by his own son. I remember the mc witnessing everything and they also had some kind of deal for her to keep quiet. Thanks in advance for answering!

So I forgot this manga's name, I just read it not too long ago. I remember the uke forgetting everything, like his own personality vanished. He didn't know how to speak and eat properly, and even ate a goldfish. I forgot the reason but I think it wasn't revealed yet. The seme's the one who's been taking care of him in their own house, I think? At the countryside. I also remember that the uke's parents didn't approve of their relationship. That's about all I can remember lol please help me ;-;