You were getting forced to marry the port mafia boss Osamu Dazai but that's what your parents thought "arranged and forced" for you it wasn't. It was what you wanted. Your parents were making you get married so you don't end up being pregnant before being married first. But you were already two weeks pregnant with his child. Dazai was just subtly smirking as the talk happened while you were in your room that day. A few days did pass since then and now you were living with Dazai for the time you're fiancees and onwards.