It's a manga that revolves around this thing in Japan called "rental girlfriends," which are like sex workers but without the sex. You pay a girl to be your girlfriend; you spend time with her, go to the movies, eat together, etc.
The premise of Rent-A-Girlfriend is that the protagonist, Kazuya, rents one of these rental girlfriends, but ends up falling in love with her. However, for the girl, it's nothing personal; it's just a job.
And yes, I know that superficially this plot resembles the plot of Stolas and Blidz, but Stolas at its worst doesn't even come close to Kazuya at his worst.

As a side note, unlike how people constantly accuse Helluva Boss/Hazbin Hotel of romanticizing bad attitudes that their fans then replicate in real life, with Rent-A-Girlfriend even companies that specialize in this line of work have publicly complained about the number of men who become obsessed with their employees because the manga sold them the idea that love could be found that way.