I Hwangjeneun Gyeolhon Sagireul Chimnida

Story

Just as I was getting used to a novel where I’d been possessed by an unstoppable will to survive, an unusual little kid rolled into my life. It was hard enough just to make ends meet, but I couldn’t turn away from those cute little eyes, so I raised him with all my care. “I’m going to marry you. Sign the marriage registration form for me.” “Later, later~ If you still feel the same way when you’re all grown up, then write your name down.” Since minors aren’t even eligible to file, I just signed it as a joke, but they say the marriage registration was accepted?

Synopsis via AniList (English).