Manga by author Akane Tama

Lucienne, a sharp-tongued marquis's daughter, and Jade, the perfect but insufferable son of a duke, can't stand each other. But one night, Lucienne dreams of a future where their child becomes the savior who prevents an imperial invasion. To protect the kingdom, she decides to do the unthinkablepropose they have a child together. When she finally asks, Jade doesn't hesitate: "Prepare yourself," he says, and pushes her down!?