Being safe in the end is guaranteed (7)
I believe the answer is:
ensured
'is guaranteed' is the definition.
(I've seen this before)
'being safe in the end' is the wordplay.
'being safe' becomes 'sure' (I've seen this before).
'in' means one lot of letters goes inside another.
'sure' inserted inside 'end' is 'ENSURED'.
(Other definitions for ensured that I've seen before include "Made certain for end user" , "Make certain of" , "Determined" , "Made certain, clinched" , "Saw to it" .)