Believe this may be on the cards (6)
I believe the answer is:
credit
'believe' is the definition.
(I know that credit is a type of trust)
'this may be on the cards' is the wordplay.
I cannot really see how this works, but
'on' could be 're' ('on' can be mean 'with reference to') and 're' is found in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for credit that I've seen before include "Commendation; tick" , "Due recognition for kind of loan?" , "Belief; tick" , "Ascribe" , "Positive bank balance" .)