Bara-hime to Koori Ouji no Harannaru Kekkon

Angelica, a princess who grew up in the slums and was treated poorly, is ordered to marry for political reasons. Her partner is Abel, the first prince of the imperial kingdom, who is feared as a "mother killer." However, in reality, he is a surly but kind-hearted, beautiful boy! With no backing, Abel is driven into a corner as nobles who are vying for the right to inherit the throne try to kill him, but the two join forces to pull off a brilliant reversal! A thrilling reversal story and a Cinderella romance!

(Source: Kadokawa, translated)