Anagram help!

[rubberneck]

Could someone offer a clue to answering this?

Which words that are anagrams of each other should replace the blanks so the below sentence reads logically?

"The _____ of the task did not dampen his _______ enthusiasm for deciphering obscure hieroglyphics"

[panurge]

Another Great FUN Quiz question which Bill Maclagan has specifically requested are not touted in this fashion.