Remarks made when on a date in Rome (6)
I believe the answer is:
asides
'remarks' is the definition.
(I have seen 'Incidental remarks' mean 'asides' so perhaps 'remarks' could also mean 'asides')
'when on a date in rome' is the wordplay.
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'on' means one lot of letters go next to another (in a down clue, letters appear on others).
'a date in rome' becomes 'ides' (Roman calendar term, as in the Ides of March).
'as'+'ides'='ASIDES'
'made' acts as a link.
(Other definitions for asides that I've seen before include "Remarks to an audience" , "Undertones on stage" , "Players aren't meant to hear these" , "Actors' remarks in an undertone" , "Daises (anag.)" .)