No doubt convinced, stop it! (4,6)
I believe the answer is:
sure enough
'no doubt' is the definition.
(both are used when discussing predictions)
'convinced stop it' is the wordplay.
'convinced' becomes 'sure' (similar in meaning).
'stop it' becomes 'enough' (both can be used to tell someone to stop something).
'sure'+'enough'='SURE-ENOUGH'
(Other definitions for sure enough that I've seen before include "Having sufficient confidence" , "as you'd expect" .)