The rule of deadly silence applies here. A moment he utters a word, he sacrifices his kingdom. This is not a difficult rule to follow if you have studied in the schools of magic and interacted with the wise. Those who have at least a minimal knowledge of magic or who can read minds will survive. The rule allows you to know the other person better and to predict their actions from their body language - it never lies, unlike words. According to its original meaning, breaking it is a great disrespect and may even be punishable by death, but in modern times, it is seen as a little more lenient. I'll let you in on a secret: sometimes magic may not work in a place where this rule applies. You are rewarded if you follow this rule by being able to choose one of the guardians of your kingdom.