Top detective tried desperately to arrest that man, but wasn’t confident (8)
I believe the answer is:
dithered
'wasn't confident' is the definition.
The definition suggests a past participle verb which matches the answer.
'top detective tried desperately to arrest that man' is the wordplay.
'top' indicates taking the first letters.
'desperately' indicates an anagram.
'to arrest' indicates putting letters inside.
'that man' becomes 'he' (pronoun for a man).
The first letter of 'detective' is 'd'.
'tried' anagrammed gives 'itred'.
'itred' enclosing 'he' is 'ithered'.
'd'+'ithered'='DITHERED'
'but' acts as a link.
Can you help me to learn more?
(Other definitions for dithered that I've seen before include "Was undecided" , "was vacillating?" , "Vacillated indecisively" , "Hesitated" , "Was hesitant" .)