As William received the heart, Aiur told him, "In Currere, it can create a domain that cancels out all magic for you. As long as you're in the domain, all spells that go against the laws of reality will disappear. Only the laws of Currere will work… But that's not the most important thing it does."
"What is its most important function?" William asked without thinking.
"You won't want to use it." Aiur replied, but she went on, "The Ironstone Pact will be your last resort. It can seal off the last bit of hope in your worst moment."
She didn't explain why he would end up in his worst moment or how to seal off the last bit of hope.
Don't ask. If you ask, the answer is 'can't say. You have to comprehend it yourself.'
It was as if an unseen existence was watching their every move. Once the keyword was detected, it would alert them at the speed of light.
Forget it…