https://www.dlsite.com/books/work/=/product_id/BJ01170701.html
As always, please support the artist and buy his works.

How to corrupt a high-handed young lady [18+]

"Your fiance's future depends on you."
I, Minase Mio, am a very special person who has a very good-looking, wealthy father and a high-spec fiancée.
The video streaming she does as a hobby regularly catches fire, but she doesn't mind because it's just a poor man's jealousy. She wants to leave the company as soon as possible, but she reluctantly goes to work to be the apple of the men's eye.
Then, Suzuki, a dull man in the accounting department, calls her in... "Did you know that your fiancé is embezzling company money?"
I can't believe what this creepy guy says, but he tells me that if I agree to his demands, he will keep it a secret....

Same author: https://comiko.net/series/130675/the-mysterious-girl-who-sits-next-to-me