Sensed compassion, initially, is genuine (9)
I believe the answer is:
heartfelt
'genuine' is the definition.
(thesaurus)
'sensed compassion initially' is the wordplay.
'sensed' becomes 'felt' (synonyms).
'compassion' becomes 'heart' (I've seen this before).
'initially' says to put letters next to each other (some letters go before others).
'felt' after 'heart' is 'HEARTFELT'.
'is' acts as a link.
(Other definitions for heartfelt that I've seen before include "Profound" , "Let father have deep and earnest kind of emotion (9)" , "Sincerely intended with strong feeling" , "With sincere passion" , "Deeply sincere" .)