Wrath does not like the idea of making a deal where he owes something he does not yet know about, but their time does appear to be limited. It is useless to push for an answer, and he is aware he will owe Five if he makes it to the other side of this (and he is determined to do that so he will not leave Emilia here alone). It is not that he thinks he can die, but for all he knows 'dying' here results in him being transported back to Hell with no way to return.

Five's question is not one he wants to answer. He knows better than to reveal any weakness. Lessons learned through ancient history. Brutal lessons he could never forget. But instead of not answering at all, he is vague about its effects (failing to mention the powers it appears to be ripping from him one after another).

"I feel... weak."

The way he says the last word makes it clear he is unaccustomed to feeling like that.

"...are you ready?"