Dalbin Doseogwan

In an empire where women are forbidden from learning the ancient language, Luna cross-dresses as "Lou" to work as an ancient language translator. Sure, her actions are punishable by death, but what haunts her more are the depressing details of her future self's diary from the mysterious library in her dreams. Making money as a translator is the fastest way she can leave her uncaring uncle's house and change her dismal future. However, Luna's main client happens to be her cousin's fiance, Duke Rothenbern, who gets drugged with a potent love potion and needs her "assistance" detoxifying it...

(Source: Tappytoon)