Tsundere Men Have the Best Luck

From the back cover

A broke young woman transmigrates into a cliché high-society romance novel as the newly bankrupt heiress Mia Monroe, the heroine every man supposedly adores. At a private club, the arrogant villain Tim Thorne offers a million dollars for a single kiss, expecting her to flee in humiliation.

Instead, she sits on his lap and kisses him repeatedly, walking away with a thirty-five-million-dollar check. A System then reveals that Tim's affection, currently at five percent, must reach one hundred percent within one month for her to stay in this world forever.

When Tim demands she pose as his girlfriend for a month, she sees her opening. But the original plot is already off the rails, and winning over a narcissist who watched security footage all night proves a strange game.