Verbal guarantee on land (6)
I believe the answer is:
ashore
'on land' is the definition.
(synonyms)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for ashore that I've seen before include "Off the boat" , "Aground" , "Onto land (from the water)" , "On(to) dry land" , "Hoarse (anag)" .)