Bound to show confidence in audition (7)
I believe the answer is:
trussed
'bound' is the definition.
(trussing is a kind of binding)
'confidence in audition' is the wordplay.
'confidence' becomes 'trust' (synonyms).
'in audition' shows a homophone (sound like) (audition can mean hearing).
'trust' is a homophone of 'TRUSSED'.
'to show' acts as a link.
(Other definitions for trussed that I've seen before include "Tied up" , "Bound up tightly" , "with restrictions on members" , "Bundled up" , "Dusters (anag) - bound" .)