The obsessed prince wants to make me the heroine

Out of boredom, Diana read the novel ' the tree of life'. She thought it was ok but could be better, like the heroine could need less saving from the male leads. She also wondered how a heroine waiting for help, could defeat 4 cool villainess with a swipe of her hand.
I could do better if I were them.
Then, she woke up in the body of one of the villainess. Diana the fire witch.
Who dies from being drowned by her finance the prince.
She came up with a plan to enjoy life, and spend a lot of money.
But, the prince is acting strange but I have done nothing at all.
"I love you, if you ever leave me I would go crazy. I could end up hurting you and I don't Want to do that" he said with a smile on his face.

A KR novel fan

This is my first writing.

It has a bit of bad language and smut

The picture used in this are not mine.