Trustworthy channel (5)
I believe the answer is:
sound
I believe this clue is a double definition.
'trustworthy' is the first definition.
(thesaurus)
'channel' is the second definition.
(I know that sound is a type of channel)
(Other definitions for sound that I've seen before include "Safe" , "Ocean inlet or deep bay" , "Financially stable" , "Health - noise" , "well" .)