Tied up reportedly for safekeeping (5)
I believe the answer is:
trust
'safekeeping' is the definition.
(thesaurus)
'tied up reportedly' is the wordplay.
'tied up' becomes 'trussed' ('truss' can be a synonym of 'tie up').
'reportedly' shows a homophone (sound like).
'trussed' sounds like 'TRUST'.
'for' is the link.
(Other definitions for trust that I've seen before include "Unit of NHS organisation" , "Fidelity" , "commercial credit" , "Hope, expect" , "Pin one's faith on" .)