I became a villainess when I was supposed to become a hero, defeat the Demon King, and marry the princess!

I was summoned from another world to become a hero, and together with my unique companions, I defeated the Demon King. I thought I could finally marry the princess of my dreams! But then, due to the Demon King's final curse (harassment), I was turned into a girl. And on top of that, I became a villainess?! This is too much!! I've become a villainess, but I'll do my best to return to my original body. Oh, and I won't forgive that handsome prince who's flirting with another woman while having a fiancée.