Akujo wa Kouri no Prince-kun wo Name Tsukusu

Koyuki, who worked at an ice cream shop, suddenly finds herself reincarnated as the villainess Freesia. Her new destiny? To be killed by her step-brother, the "Ice Prince" Cecil. But for Koyuki, there's an even bigger problem: this new world has no ice cream! She comes up with a plan: "If I befriend Cecil and open an ice cream shop, everything will be solved, right?" As Koyuki begins her quest to create an ice cream shop in this new world, her "charming skills" start to attract an increasing number of people who dote on her…and Cecil's affection is the most intense of all! "You're the one who made me this way, big sister... So take responsibility!

Original Webtoon:
Piccoma, MechaComic, Comico