Questionable space for sweetheart to get free (6)
I believe the answer is:
escape
'get free' is the definition.
'questionable space for sweetheart' is the wordplay.
'questionable' is an anagram indicator.
'for' says to put letters next to each other.
'sweetheart' becomes 'e' (the heart/centre of 'sweet').
'space' with letters rearranged gives 'escap'.
'escap'+'e'='ESCAPE'
'to' is the link.
(Other definitions for escape that I've seen before include "Gain freedom" , "Getaway" , "has to fly" , "An outburst" , "issue" .)