Reluctant to say she has no heart (6)
I believe the answer is:
averse
'reluctant' is the definition.
(averse can mean reluctant or opposing)
'say she has no heart' is the wordplay.
'say' becomes 'aver' (aver means to state or claim something).
'has no heart' suggests removing the centre.
'she' with its centre removed is 'se'.
'aver'+'se'='AVERSE'
'to' acts as a link.
(Other definitions for averse that I've seen before include "Strongly opposed (to something)" , "Antipathetic" , "Ill-disposed to (a poem?)" , "Reaves (anag)" , "Indisposed" .)