Sentimental woman gets nothing in return (7)
I believe the answer is:
maudlin
'sentimental' is the definition.
(synonyms)
'woman gets nothing in return' is the wordplay.
'woman' becomes 'maud' (woman's name).
'gets' is a charade indicator (letters next to each other).
'nothing' becomes 'nil' (eg nil is zero in football).
'in return' shows that the letters should be reversed in order (return can mean to go backwards).
'nil' backwards is 'lin'.
'maud'+'lin'='MAUDLIN'
(Other definitions for maudlin that I've seen before include "Over-emotional" , "Sentimentally tearful" , "Soppy, lachrymose" , "Sloppily sentimental, perhaps due to drink" , "Effusively or insincerely emotional" .)