Confirm result's about right (6)
I believe the answer is:
Here is my best explanation:
'confirm' is the definition.
'result's about right' is the subsidiary indication.
'result' becomes 'ensue' ('ensue' can be a synonym of 'result').
'about' means one lot of letters goes inside another.
'right' becomes 'r' (common abbreviation).
'ensue' placed around 'r' is 'ensure'.
(Other definitions for ensure that I've seen before include "Make certain, confirm", "See run (anag)", "Make certain, secure", "Make certain (something will occur)", "Guarantee", "Make certain or safe", "Make certain, clinch" and "Make certain that (something occurs)".)