Happy with jewel secure in case (9,3)
I believe the answer is:
gladstone bag
'case' is the definition.
(Gladstone bag is an example)
'happy with jewel secure' is the wordplay.
'happy' becomes 'glad' (similar in meaning).
'with' is a charade indicator (letters next to each other).
'jewel' becomes 'stone' (gem stone).
'secure' becomes 'bag' (bag can mean to secure).
'glad'+'stone'+'bag'='GLADSTONE BAG'
'in' acts as a link.
(Other definitions for gladstone bag that I've seen before include "hand luggage" , "Briefcase-like container" , "Small portmanteau" , "case" , "Large old portmanteau" .)