Added 12 minutes later
Well, here's something like a riddle. But it's quite easy because I'm not good at making them up.
There are three kingdoms, let's call them Fus, Ro, and Da. The king of Fus wants to marry his daughter to the prince of Ro, but if he does, the kingdom of Da threatens to declare war. The kingdom of Da is more powerful than the kingdoms of Fus and Ro. What is the reason for this behavior of the kingdom of Da?