It is almost inconceivable, as one would never think that a royal family would have raised a child to be so little knowledgable about this world. The Princess had a vague understanding of people, though her common sense was lacking. She was obviously not familiar with the risks involved with fighting monsters and would commonly approach them. It's similar to a child looking at a dog that they have only seen in books, thinking that it is safe to pet it because no one said it is dangerous.