The Readymade Queen 

After her house falls to ruin, Abigail Dilloa is relegated to serving an imprisoned princess for the rest of her life. Just as she finally comes to terms with her fate, assassins murder the sweet princess in cold blood. Faced with the same grisly fate, Abigail's past regrets flash before her eyes, but she is saved at the last minute by Duke Lakiel de Edelgard. However, the cunning duke is hell-bent on revenge, and he gives her an ultimatum: die, or play the part of Princess Violeta in his sinister succession scheme. Now that she has become a puppet in this play, will Abigail manage to fool the world and steal the throne? Or, will the cruel politics of the palace expose her act as nothing but a sham? Based on the hit novel. (Source: Tappytoon)