A Heart for the Emperor

Our protagonist ends her day as usual, rereading her favorite novel before sleep. But, after awakening in the body of Princess Charlioni of the Kingdom of Linoa, the protagonist of that very novel, she realizes that it's only a matter of time before her kingdom is ruthlessly defeated at the hands of Casikaf, the blood-thirsty Emperor of Pretas. Fortunately, she has the upper hand of knowing that he'll fall madly in love with her at first sight. But when the novel starts veering off track and every character isn't who they appear to be, she'll have to take matters into her own hands to get her happy ending.
 (Source: Webtoon Entertainment)