As the group walked back toward the Throne Room. Applejack spoke up. "Mind telling us what's up with oath you made Twilight?"
"Yeah" Pinkie piped up. "I thought a Pinkie Promise was the only kind?"
Twilight shook her head. "Its a very rare type od magic. Only known to a select few unicorns."
"And alicorns." Princess Celestia said. "I have not heard one being made in a very long time."
"So what is it?" Fluttershy asked.
Twilight stopped. "Before I explain it, Pinkie. In case somepony broke a Pinkie Promise. What would you do?" Pinkie opened her mouth "And I mean, what would you really do? Something physical?"
Pinkie began to replie but stoped. "Um... You know what. I don't know what I'd do! No pony's ever broken one, so I can't say what I'd do."
Twilight nodded. "Well this oath is something that does something to stop me. I physically can not say anything about what Flare showed me. My magic would literally keep my mouth shut."
And somethings, she thought, should have remained lost and forgotten in a long dead past.