19-year old Narika Yoshikawa lived a poor life with her single mother. But when Narika's mother passed away, she was forced to follow in her mother's lifestyle, which unfortunately, also included her debts. One night, some men come to her door and demand 3 million yen that Narika's mother borrowed from them. She's saved by a strange man who pays the money to the men, and tells Narika that he just "bought her" and if she marries him, he will give her anything she wants!

source: https://www.mangaupdates.com/series/2rw8t0l/happy-trouble-wedding