Troubled aunt gets to recover — of course! (9)
I believe the answer is:
naturally
'of course' is the definition.
(synonyms)
'troubled aunt gets to recover' is the wordplay.
'troubled' indicates anagramming the letters.
'gets' means one lot of letters go next to another.
'to recover' becomes 'rally' (rallying is a kind of recovering).
'aunt' anagrammed gives 'natu'.
'natu'+'rally'='NATURALLY'
(Other definitions for naturally that I've seen before include "In an artless way" , "as normal" , "As a matter of course" , "Unforced" , "without medical assistance" .)