Ryuuou-sama wa Metoritai!

After his mother's death, Hikaru has a change of heart, and stops being delinquent. He starts looking for a decent job, but he never passes the final interviews and keeps failing. A sudden recruiting email he receives is like pennies from heaven, so he goes to the interview. There, a handsome man, Louis, appears and Hikaru is transferred to another world. Louis reveals his true appearance as a huge dragon and informs Hikaru that they are in the kingdom of miracles. Now the dragon's mark appears on Hikaru's belly, and he is told that he has been chosen as a bride of the Dragon King!

(Source: Takeshobo)