Date for betrothal? (10)
I believe the answer is:
engagement
I believe this is a double definition.
'date' is the first definition.
(I know that date can be written as engagement)
'betrothal?' is the second definition.
(synonyms)
'for' acts as a link.
(Other definitions for engagement that I've seen before include "Fight" , "calls for signs of commitment" , "Gig" , "pledge between 11 & 6 [WILLIAM & KATE]" , "Agreement to marry" .)