Banter in bar getting really heartless, sadly (8)
I believe the answer is:
Here is my best explanation:
'banter' is the definition.
('raillery' can be a synonym of 'banter')
'bar getting really heartless sadly' is the subsidiary indication.
'bar' becomes 'rail' (rail is a kind of bar**).
'getting' is a charade indicator (letters next to each other).
'heartless' says to hollow out the word (remove centre letters).
'sadly' is an anagram indicator.
'really' with its centre removed is 'rely'.
'rely' anagrammed gives 'lery'.
'in' is the link.
(Other definitions for raillery that I've seen before include "Banter, back-chat", "Satirical banter", "Good-humoured teasing", "(Example of) banter", "Light teasing repartee", "Badinage" and "Playful satire".)