Encouragement sensed as sincere (9)
I believe the answer is:
heartfelt
'sincere' is the definition.
(similar in meaning)
'encouragement sensed' is the wordplay.
'encouragement' becomes 'heart' (as in taking heart from something).
'sensed' becomes 'felt' (synonyms).
'heart'+'felt'='HEARTFELT'
'as' acts as a link.
(Other definitions for heartfelt that I've seen before include "Let father have deep and earnest kind of emotion (9)" , "Kindly" , "unfeigned sincerity" , "Deeply sincere" , "Most fervent in cardiac way" .)