Get up reliable piece of information, shortly accepted (7)
I believe the answer is:
surface
'get up' is the definition.
(surface can mean to come up or rise)
'reliable piece of information shortly accepted' is the wordplay.
'reliable' becomes 'sure' (similar in meaning).
'piece of information' becomes 'fact' (I've seen this in another clue).
'shortly' means to remove the last letter.
'accepted' means one lot of letters goes inside another.
'fact' with its final letter taken away is 'fac'.
'sure' placed around 'fac' is 'SURFACE'.
(Other definitions for surface that I've seen before include "Outside; rise to the top" , "Top side" , "Superficial appearance" , "Worktop" , "In water, come to the top" .)