Since France was young he always had a fear of water. He hates large bodies of water and even small lakes and ponds. They disturb him to the point he can barely stand near them without starting to feel sick and shake with fear.
He never directly admitted to anyone except China that he was scared of water. At first China wasn’t too concerned about it. It wasn’t an uncommon fear and he didn’t consider it a huge deal, so they quickly dropped the topic. It was only one day when France, China and South Korea were spending time next to China’s fish pond did he realize the extent of France’s fear. China noticed France seemed a little unnerved already, but when South Korea playfully pushed France into the pond was when all hell broke loose.
France screamed hysterically, kicking his legs and thrashing his arms about. He clawed at the water, too frightened to look for the edge to climb out. China nearly panicked himself with how France was acting, but he quickly recovered and pulled him out of the water. He forced him to stand so he could get him away from the water, but afterwards they sat in his room, China cradling him until he calmed down.
From that day forward China decided to do everything in his power to keep France away from water. He promised to protect him from it and never let it hurt him. He swore to France that no matter what he would never let him drown.