Raido Kuroki

Have you ever had your life turn 180 degrees in just half an hour?
And now I'm standing here, being dressed in my older sister's wedding gown. She was supposed to marry a Yakuza today, but she ran off at the last minute with her lover. And I was forced to stand in her place until she was caught. It's not in the family's best interest to break off the marriage, because revenge can be expected from Lord Kuroki-kai. He chose my sister when they were still children, and to break that deal would mean sending the entire family to their deaths.
The most important thing now is to get my sister back before the fabric is removed from my face, otherwise he might get angry when he sees me. After all, I'm much younger than her, even though we look alike. Although I'm also quite beautiful for my age, he clearly won't appreciate it. My sister has a nice, curvy figure, while mine is just starting to grow and is very small and delicate, which only emphasizes my age.
(the main character is a girl)