Expensive; sweet (4)
I believe the answer is:
dear
I believe this clue is a double definition.
'expensive' is the first definition.
(similar in meaning)
'sweet' is the second definition.
(both are terms of endearment)
(Other definitions for dear that I've seen before include "Honey - costly" , "Baby" , "At a high cost" , "Expensive or loved" , "close" .)