PLEASE HELP

Please help me find a bright and cute manhwa that I’ve been thinking about. There’s a scene with a little blonde baby prince who’s going through a hard time because his brother treats him badly. Then there’s another kid—he’s the older brother of the female lead—with a soft silver or bluish bob haircut and bangs. Even though he’s still a kid, he becomes friends with the baby prince, and they start writing letters to each other and become pen pals. That’s all I remember, but I really hope to find it again.