Judge to cover 'topless trial' in Express again (7)
I believe the answer is:
restate
'express again' is the definition.
('state' is an answer for 'express' so perhaps 'restate' is OK for 'express again')
'judge to cover topless trial' is the wordplay.
'judge' becomes 'rate' (rating is a kind of judging**).
'to cover' is an insertion indicator.
'topless' means to remove the first letter.
'trial' becomes 'test' ('test' can be a synonym of 'trial').
'test' with its first letter removed is 'est'.
'rate' going around 'est' is 'RESTATE'.
'in' is the link.
(Other definitions for restate that I've seen before include "Go over" , "say, a different way" , "say, in other words" , "Once more affirm" .)