Guarantee safety (8)
I believe the answer is:
security
This clue is a double definition.
'guarantee' is the first definition.
(I know that security is a type of guarantee)
'safety' is the second definition.
(I know that security is a type of safety)
(Other definitions for security that I've seen before include "Safety; collateral" , "Something given to guarantee payment" , "cover" , "I curtsey in state of safety" , "Protection from damage" .)