Stimulate change seeing hesitation within (8)
I believe the answer is:
energise
'stimulate' is the definition.
('energise' can be a synonym of 'stimulate')
'change seeing hesitation within' is the wordplay.
'change' is an anagram indicator.
'hesitation' becomes 'er'.
'within' indicates putting letters inside.
'seeing' anagrammed gives 'engise'.
'engise' placed around 'er' is 'ENERGISE'.
(Other definitions for energise that I've seen before include "To banish inertia" , "Stimulate activity" , "Give active force" , "give vigour" , "Motivate" .)