Self-assurance (5)
I believe the answer is:
poise
'self-assurance' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for poise that I've seen before include "Self-confidence" , "Aplomb" , "Graceful and elegant bearing in a person" , "Dignity and assurance of manner" , "Elegance" .)