The reusable Oath of Truth is a rare arcane contract.The reusable Oath of Truth is a contract spell made for those who activated it are unable to lie in a ten-minute period.
This contract spell would stay latent until activated by a trigger spell. The person who activated it would then be put under the contract. While the contract spell is active, it would limit the actions the person can take in such a way that he does not break the contract. Unlike traditional contract scrolls which were one usage only, this particular one was reusable. As such, it was very hard to create and, therefore, pricey.