Synopsis: The Reincarnated Heroine Has Fallen For Her Rival

I finally got reincarnated as the heroine of a manga, but… what do you mean I’m at the condemnation scene?! So now I have to marry a cold-hearted scumbag, endure five years of humiliation, and be nothing more than a stepping stone for him to reunite with his first love?! Excuse me—what kind of doormat heroine nonsense is this?!