In the finish, I get the girl (4)
I believe the answer is:
'the girl' is the definition.
'in the finish i' is the wordplay.
'in' means one lot of letters goes inside another.
'the finish' becomes 'end' (I've seen this before).
'end' placed around 'i' is 'ENID'.
'get' is the link.
(Other definitions for enid that I've seen before include "'... Blyton, children's author (4)'", "Woman", "- Blyton, twentith century writer", "Dine with Ms blyton, writer", "Geraint's loved one".)