Awfully eager to assent (5)
I believe the answer is:
agree
'assent' is the definition.
(I know that assent is a more specific form of the action agree)
'awfully eager' is the wordplay.
'awfully' is an anagram indicator.
'eager' anagrammed gives 'AGREE'.
'to' is the link.
(Other definitions for agree that I've seen before include "confess?" , "'Birds in their little nest . . . . .'" , "Hold the same view" , "Eager (anag)" , "grant" .)