Charming conclusion, acquiring sensitivity to music (9)
I believe the answer is:
endearing
'charming' is the definition.
(I've seen this before)
'conclusion acquiring sensitivity to music' is the wordplay.
'conclusion' becomes 'ending' (synonyms).
'acquiring' indicates putting letters inside.
'sensitivity to music' becomes 'ear' (as in having an ear for music).
'ending' going around 'ear' is 'ENDEARING'.
(Other definitions for endearing that I've seen before include "delightful" , "Engaging" , "Inspiring affection" , "Disarming" , "Charming" .)