Rook determined to see bear out (7)
I believe the answer is:
confirm
'bear out' is the definition.
(thesaurus)
'rook determined' is the wordplay.
'rook' becomes 'con' (synonyms).
'determined' becomes 'firm' (I've seen this before).
'con'+'firm'='CONFIRM'
'to see' acts as a link.
(Other definitions for confirm that I've seen before include "Make (provisional arrangement) definite" , "Establish the truth of" , "Strengthen" , "Provide support for the truth" , "Substantiate" .)