Attempt to confine soldiers craving betrayal (9)
I believe the answer is:
treachery
'betrayal' is the definition.
(I know that betrayal can be written as treachery)
'attempt to confine soldiers craving' is the wordplay.
'attempt' becomes 'try' (synonyms).
'to confine' is an insertion indicator.
'soldiers' becomes 're' (Royal Engineers).
'craving' becomes 'ache' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
're'+'ache'='reache'
'try' enclosing 'reache' is 'TREACHERY'.
Can you help me to learn more?
(Other definitions for treachery that I've seen before include "perfidious conduct" , "Perfidy" , "Perfidious behaviour" , "lack of loyalty" , "Two-timing" .)