Lady dives into trouble deliberately (9)
I believe the answer is:
advisedly
'deliberately' is the definition.
(synonyms)
'lady dives into trouble' is the wordplay.
'into trouble' indicates an anagram.
'lady'+'dives'='ladydives'
'ladydives' with letters rearranged gives 'ADVISEDLY'.
(Other definitions for advisedly that I've seen before include "following guidance?" , "with due consideration" .)