Her love's a lifesaver? (4)
I believe the answer is:
hero
'a lifesaver?' is the definition.
(I've seen this in another clue)
'her love's' is the wordplay.
'love' becomes 'o' (love means zero in tennis).
'her'+'o'='HERO'
(Other definitions for hero that I've seen before include "eg Hercules" , "Priestess at Sestos" , "paragon" , "Leander's lover - a person of courage" , "Leading male role" .)