Herald sure to be transported (10)
I believe the answer is:
spellbound
'be transported' is the definition.
(both can mean fascinated or enraptured)
'herald sure' is the wordplay.
'herald' becomes 'spell' (spell can mean to herald or signal).
'sure' becomes 'bound' (synonyms).
'spell'+'bound'='SPELLBOUND'
'to' is the link.
(Other definitions for spellbound that I've seen before include "frozen" , "appear hypnotised" , "attending solidly" , "Fascinated" , "Rooted to the spot" .)