Assess the value of (8)
I believe the answer is:
appraise
'assess the value of' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for appraise that I've seen before include "Assess, set a price on" , "Decide the value or quality of" , "survey?" , "Tip off" , "Assess value of (something)" .)