More confident bachelor, more mature (6)
I believe the answer is:
bolder
'more confident' is the definition.
('bold' can be similar in meaning to 'confident')
'bachelor more mature' is the wordplay.
'bachelor' becomes 'b' (abbreviation e.g. BA=Bachelor of Arts).
'more mature' becomes 'older' ('old' is associated in meaning with 'mature').
'b'+'older'='BOLDER'
(Other definitions for bolder that I've seen before include "More impudent or daring" , "Less shy" , "Braver or cheekier" .)