Akujo no Label wo Harareta Tsuihou Reijou Desu ga, Saikyou Heika no Dekiai ni Tsukamarimashita

Estar is an herbalist working at a botanical garden in the Kingdom of Blutoire. She is fed up with Grayson, the Garden owner's son, following her around every day. Full of jealousy, Grayson's fiancée Katia frames Estar and makes her appear as a "villainess" who poisoned and attempted to murder her. Unable to prove her innocence, she is exiled from her homeland. When she is attacked by wild dogs while wandering in the woods by herself, she is saved by King Lacelvist, the ruler of a neighboring kingdom, known for being ruthless and without a shred of mercy in his heart. And, due to certain circumstances, she ends up pretending to be his fiancée! Immerse yourself in a romantic fantasy that begins with a fake engagement between a girl branded as a villainess and a fearsome king rumored to be a ruthless beast!
(Source: MangaPlaza)