Great, sweetheart, yours truly's not without love (7)
I believe the answer is:
eminent
'great' is the definition.
(synonyms)
'sweetheart yours truly's not without love' is the wordplay.
'sweetheart' becomes 'e' (the heart/centre of 'sweet').
'yours truly's' becomes 'mine' (belonging to the person speaking or writing).
'without' suggests deleting specific letters.
'love' becomes 'o' (love means zero in tennis).
'not' with 'o' taken away is 'nt'.
'e'+'mine'+'nt'='EMINENT'
(Other definitions for eminent that I've seen before include "Outstanding or distinguished (7)" , "Illustrious like cardinal?" , "Distinguished and admired" , "Famous and admired" , "High" .)