Switching nations

"Now, Edelgard here isn't just from Adrestia," said Henry to his empty office. "She's the princess of Adrestia. But what if we made her believe she was from...somewhere else? When I snap my fingers, Edelgard, you'll wake up and believe you're from the Leicester Alliance. In fact, you'll believe you're it's princess and get mad any time I ask about Adrestia."

He decided to go a bit further with this. "Edelgard, you believe all women in the Alliance, including its future rulers, must be naked when in a man's presence. It's not odd in any way, just 'your' culture. Also, anything I tell you about the Alliance will immediately become true to you, even if it's totally unbelievable. Got all that?"

"Yes, sir," Edelgard droned.

"Sir, how quaint," Henry chuckled.