Sinners Anonymous by Somme Sketcher

The story follows Rory, a young woman desperately trying to escape a dark past and build a normal life. She takes a job answering the phones at a hotline called "Sinners Anonymous"—a place where anonymous callers confess their darkest secrets.

One night, a mysterious, deeply intimidating man calls. He doesn't confess a sin; instead, he speaks with a chilling, hypnotic authority that leaves Rory completely unsettled.

That caller is Angelo Visconti, the ruthless, cold-blooded underboss of the New York Cosa Nostra mafia. Angelo becomes entirely obsessed with the voice on the other end of the line. But there is a massive twist: in the real world, Rory is engaged to Angelo's younger brother as part of an arranged marriage meant to secure her safety. Angelo has no idea that the quiet, submissive girl promised to his brother is the exact same captivating woman he talks to on the phone.