Reckless Cinders it turned out embraces sweetheart (10)
I believe the answer is:
indiscreet
'reckless' is the definition.
(indiscreet can mean reckless or unwise)
'cinders it turned out embraces sweetheart' is the wordplay.
'turned out' indicates an anagram (turn out can mean to organise).
'embraces' is an insertion indicator.
'sweetheart' becomes 'e' (the heart/centre of 'sweet').
'cinders'+'it'='cindersit'
'cindersit' with letters rearranged gives 'indiscret'.
'indiscret' placed around 'e' is 'INDISCREET'.
(Other definitions for indiscreet that I've seen before include "Too ready to tell secrets" , "Injudicious (anag of 6, 9 and 23)" , "Imprudent -- 10 across (anag)" , "Reckless" , "shameless" .)