It’s a girl’s sort of paper (6)
I believe the answer is:
tissue
'sort of paper' is the definition.
'it's a girl's' is the wordplay.
I cannot quite see how this works, but
'it's' could be 'tis' (I've seen this before) and 'tis' is present in the answer.
'girl' could be 'sue' (girl's name) and 'sue' is located in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for tissue that I've seen before include "cell block?" , "Suddenly leave in protest" , "Web; fabric" , "'Soft, thin paper (6)'" , "Disposable piece of absorbent paper" .)