Not expecting the girl to have the goods (8)
I believe the answer is:
unawares
'not expecting' is the definition.
(I've seen this before)
'girl to have the goods' is the wordplay.
'girl' becomes 'Una' (girl's name).
'to have the goods' becomes 'wares' (I can't explain this - if you can you should believe this answer much more).
'una'+'wares'='UNAWARES'
'the' acts as a link.
Can you help me to learn more?
(Other definitions for unawares that I've seen before include "Without knowledge of the situation" , "without realising" , "Off guard" , "Unexpectedly - suddenly" , "Be taken thus if off-guard" .)