Since I Wasn't Chosen as the Fiancée, I'll Rewrite My Fate with the Grim Reaper!

Marquis Manoa was attending a royal tea party with her fianc. He was supposed to have a good time, but the moment he took a sip of tea, he suddenly collapsed due to shortness of breath. Just before she lost consciousness, she saw her fiance running to help another young lady. When Manoa wakes up, the g** of death appears in front of him and says, "I've come to get your soul."