A girl's confused about note? Capital! (7)
I believe the answer is:
algiers
'capital' is the definition.
(capital of Algeria)
'a girl's confused about note?' is the wordplay.
'confused' indicates an anagram.
'about' means one lot of letters goes inside another.
'girls' anagrammed gives 'lgirs'.
'lgirs' enclosing 'e' is 'lgiers'.
'a'+'lgiers'='ALGIERS'
(Other definitions for algiers that I've seen before include "N. African port" , "NW African capital" , "North African port" , "North African capital" , "Capital city" .)