A Good Guy's Guide To Marry A Mob Boss (Manxman)

A Powerful Mob Boss one day saw a guy, nothing about him stood extraordinary, yet he could not pull his gaze away from him, because he buried a dead sparrow in his territory, and it seemed he could hear thoughts of this guy who wanted to marry him, but also carrying the order of his demise.
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Hikaru Noah Edwards is an American-Japanese, 25 five years old, not gorgeous but fine-looking guy. He has always been a reserved, compassionate, and somewhat awkward guy, and works as a librarian, however, there was a time when he always wanted to be a writer as long as he remembered since he was young, but something made him stop dreaming about it.

And, One day, Noah's mundane life turned upside down when he unexpectedly transmigrated inside a novel as an assassin who was the story antagonist's henchman. Soon, a fat cat gave him a task if he wanted to go back to the real world, and the task was to marry the protagonist. On the other hand, he was ordered to kill the story's protagonist, Angelo

Angelo Dante Moretti is an American- Italian, 33-year-old billionaire. As the eldest heir of Moretti, he is running Moretti's empire as an efficient, self-confident, and charismatic CEO of Moretti multi-millionaire Industries, who is admired, respected, and also, envied and desired by men and women. But there was a layer beneath all these layers of his, he was a ruthless mob boss of the underworld, his name was enough to make his rivals fear for their life, only If you decide to screw him, you would be doomed.

(this book was also known as mafia protagonist is interested in me)