Belief in borrowing facility (6)
I believe the answer is:
credit
'belief' is the definition.
(thesaurus)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for credit that I've seen before include "Positive balance in account" , "Good reputation; tick" , "Source of pride; account entry" , "Side of an account for payments in" , "Believe; good reputation" .)