Cited true performance shows conviction (9)
I believe the answer is:
certitude
'conviction' is the definition.
(I've seen this before)
'cited true performance' is the wordplay.
'performance' indicates an anagram.
'cited'+'true'='citedtrue'
'citedtrue' anagrammed gives 'CERTITUDE'.
'shows' is the link.
(Other definitions for certitude that I've seen before include "Feeling of surety" , "One's sure" , "A feeling of conviction, given rectitude" , "Something about which one is sure" .)