You're Ruthless, I'm Vicious, and We've Both Got Riches Ahead

A ruthless couple. A sweet-on-the-surface, sinister strong woman who transmigrates into a book x an unscrupulous villain. Readers who prefer both leads to be sexually inexperienced should steer clear.

She transmigrates into a book one day, slaps the mistress, tramples the scumbag, and will stop at nothing to climb to the top.