Points ruse out to make certain (6)
I believe the answer is:
ensure
'make certain' is the definition.
(synonyms)
'points ruse out' is the wordplay.
'points' becomes 'en' (compass points east and north).
'out' is an anagram indicator (out can mean wrong or inaccurate).
'ruse' with letters rearranged gives 'sure'.
'en'+'sure'='ENSURE'
'to' is the link.
(Other definitions for ensure that I've seen before include "Protect" , "Guarantee" , "See run (anag)" , "Make certain, secure" , "Make certain, confirm" .)