Kill for diamonds (3)
I believe the answer is:
ice
I believe this is a double definition.
'kill' is the first definition.
(ice can informally mean to assassinate)
'diamonds' is the second definition.
(slang term for diamonds)
'for' is the link.
(Other definitions for ice that I've seen before include "Diamonds (informal)" , "Skating surface" , "Cold stuff used in enticement" , "Decorate with frosting" , "Solid water" .)