Cross-Dressing Villainess Cecilia Sylvie, Vol. 1 (manga) — Hiroro Akizakura

If they find out I'm a girl, I'm toast! All I want is a peaceful, drama-free life! Maybe in the manga adaptation I can take it easy…
 
I, Cecilia Sylive, woke up as the villainess in a reverse haremdating sim world. Which, of course, means I've been fated to a Bad End no matter what -- that is, if I keep living as a girl. And so, the only way to avoid becoming a Holy Maiden Candidate and halt the death flags in their tracks is…to live as a boy! With the assistance of my brother Gilbert and a little bit of luck, maybe even I can find a happily ever after…