Love unaltered fertile spot (5)
I believe the answer is:
oasis
'fertile spot' is the definition.
(I've seen this before)
'love unaltered' is the wordplay.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'unaltered' becomes 'asis' (I've seen this in other clues).
'o'+'asis'='OASIS'
(Other definitions for oasis that I've seen before include "source of water" , "place of refuge" , "Pop group" , "water you'll want here" , "Fertile place in a desert, watering-hole" .)