Should be insured, darling (8)
I believe the answer is:
precious
'darling' is the definition.
(thesaurus)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for precious that I've seen before include "as good as gold" , "highly esteemed" , "Valuable or dearly beloved" , "Having great value" , "costly" .)