Have faith in credit (7)
I believe the answer is:
believe
This clue is a double definition.
'have faith' is the first definition.
(I've seen this before)
'credit' is the second definition.
(I've seen this before)
'in' is the link.
(Other definitions for believe that I've seen before include "Have religious faith" , "Regard as true" , "Hold as true" , "Have faith; accept" , "Trust" .)