Betabore no Kon'yakusha ga Akuyaku Reijou ni Saresou nanode.

When Crown Prince Vincent announces their engagement is over, Elizabeth faints. What will become of House la Montlivere? Of her entire family? At the prince’s side, the so-called heroine smirks. Elizabeth is doomed to a villainess’ fate… Only for the tables to turn when Vincent suddenly calls out the heroine for her misdeeds! Jump into the story of an ill-fated but handsome prince as he fights for his darling fiancée, deflecting every attempt to turn her into an evildoer by any means necessary! They’ll have their lovey-dovey happily ever after, even if it kills him! (Source: Cross Infinite World)