Honest letter in Braille, possibly (8)
I believe the answer is:
reliable
'honest' is the definition.
(I know that honest can be written as reliable)
'letter in braille possibly' is the wordplay.
'letter' becomes 'e'.
'in' is an insertion indicator.
'possibly' indicates anagramming the letters.
'braille' is an anagram of 'rliable'.
'e' going within 'rliable' is 'RELIABLE'.
(Other definitions for reliable that I've seen before include "Can be depended upon, trustworthy" , "Dependable, trustworthy" , "worthy of trust" , "Dependable, can be trusted" , "Faithful" .)