Engagement rings worn as present (6)
I believe the answer is:
donate
'present' is the definition.
(I know that donate is a type of present)
'engagement rings worn' is the wordplay.
'engagement' becomes 'date' (synonyms).
'rings' indicates putting letters inside.
'worn' becomes 'on'.
'date' placed around 'on' is 'DONATE'.
'as' is the link.
(Other definitions for donate that I've seen before include "Give to a charity or good cause" , "Give freely, maybe blood" , "Give (transplant organ)" , "Give charitably - say blood" , "Give (money) to a good cause" .)