Sing of love amid the waving corn? (5)
I believe the answer is:
croon
'sing' is the definition.
(I know that croon is a kind of sing)
'love amid the waving corn' is the wordplay.
'love' becomes 'o' (love means zero in tennis).
'amid' means one lot of letters goes inside another.
'the waving' indicates anagramming the letters (letters wave around).
'corn' is an anagram of 'cron'.
'o' going within 'cron' is 'CROON'.
'of' acts as a link.
(Other definitions for croon that I've seen before include "Sing in a soft low tone" , "Sing like Bing" , "Sing softly" , "Sing with a soft voice" .)