Believe one side of account (6)
I believe the answer is:
credit
This clue is a double definition.
'believe' is the first definition.
(I know that believe is a more specific form of credit)
'one side of account' is the second definition.
(I've seen this before)
(Other definitions for credit that I've seen before include "Direct (anag) - tick" , "Favourable balance - good repute" , "Time given to pay for goods" , "Believe - one side of an account" , "Honour or reliability - believe" .)