Suddenly Became a Princess One Day
The OG of otome isekai and transmigration. You really can't go wrong with this manhwa. Athy is brilliant, has beautiful character development- rivaled only by Claude- and is such a joy to see. She's strong, a very good leader, and not weak at all. Lucas is sexy as hell, enough said. Ijekiel is brilliant and my heart I hate that his love for Athy won't bear fruit. Jeanette is so innocent and my heart breaks for her. I could really go on and on about why I love this story, but this really is a landmark for the otome isekai genre.
Under the Oak Tree
Steamy, steamy smut which I absolutely did not expect in this genre. Excellent chemistry, and both the leads are frustrating in the best way. Edit, 03/09/21: I put this off for too long, hoping it would go over allahor cliffhangers, but I couldn't bear it anymore and ended up binging until I bit all my fingernails off. Anyway, if you haven't already heard it before,then this is phenomenal. It's so fucking good that I don't even have any accurate adjectives for this. Even if you've never ever read any manhwa that's geared towards women before, if recommend you read this.
My Fiance is in Love with My Little Sister