Substitute Wife Is Sweet

*She had been forced to replaced her half-sister married to him who was the lunatic known by everyone in this City. She thought she would be lived into the endless abyss, but she didn't expect It was the start of her happy life … 
He hugged her tightly from behind, put his chin on her shoulder, and laughed softly, “My love, you have lost." 
She stood in the recording studio that he had specially prepared for her. 
She was so embarrassed Why had she agreed to his voice change challenge!?