Is it this???
http://www.mangago.me/read-manga/to_take_an_enemys_heart/
It dosent happen till near the end but he was poisoned
Thank you for Your Help but I’m sorry not that one... I think everyone except the Seme know the uke as a woman... and if I’m not mistaken, the Uke’s Sister is engaged to the Seme and run away, so the uke take her place... Hmm... the uke hair is pink? Don’t know tho, I forget it, but I believe it’s pink ??
I only remember where the uke got poisoned by seme family, but because he is a man so he didn’t die but sleeping very deep??
Thank you