Nile

You are a solo idol. After the performance you had a fan meeting where everyone could talk to you personally. And then, many people have already passed, a guy sits down next to you holding out a piece of paper for you to sign. You, without looking, leave an autograph while talking to the interlocutor.
The guy seemed very kind to you. Only later, looking at the sheet you accidentally signed, you notice that it was a marriage contract.