Trust could be real nice (8)
I believe the answer is:
reliance
'trust' is the definition.
(I know that trust can be written as reliance)
'could be real nice' is the wordplay.
'could be' indicates anagramming the letters.
'real'+'nice'='realnice'
'realnice' is an anagram of 'RELIANCE'.
(Other definitions for reliance that I've seen before include "Banking" , "Faith" , "Trust or confidence" , "Dependence (on something)" , "Trust - in cereal (anag)" .)