Friendship? It is accepted by girl (5)
I believe the answer is:
amity
'friendship?' is the definition.
(I've seen this in other clues)
'accepted by girl' is the wordplay.
'accepted' becomes 'a' (financial abbreviation).
'by' says to put letters next to each other.
'girl' becomes 'mity' (I can't justify this - if you can you should give a lot more credence to this answer).
'a'+'mity'='AMITY'
'it is' is the link.
Can you help me to learn more?
(Other definitions for amity that I've seen before include "Friendship - goodwill" , "Accord" , "Friendliness" , "Friendly feeling, fraternity" , "Friendly relations" .)