It's justifiable for a girl to appear in a twisted belt (7)
I believe the answer is:
tenable
'it's justifiable' is the definition.
(thesaurus)
'a girl to appear in a twisted belt' is the wordplay.
'a girl' becomes 'ena' (I've seen this in other clues).
'to appear in' is an insertion indicator.
'a twisted' indicates an anagram.
'belt' is an anagram of 'tble'.
'ena' put into 'tble' is 'TENABLE'.
'for' is the link.
(Other definitions for tenable that I've seen before include "Of argument, rational and defensible" , "Able to be believed" , "okay as regards defence" , "Late Ben (anag.)" , "Based on sound reasoning or evidence" .)