That aroma nicely held over sweetheart (9)
I believe the answer is:
inamorata
'sweetheart' is the definition.
(I've seen this before)
'that aroma nicely held over' is the wordplay.
'held' says the answer is hidden in the clue.
'over' shows that the letters should be reversed in order.
'ataromani' is hidden in the letters of 'that aroma nicely'.
'ataromani' in reverse letter order is 'INAMORATA'.
(Other definitions for inamorata that I've seen before include "Someone fancies her" , "A woman loved" , "Girlfriend" , "Beloved of one another" , "Sweetheart" .)