Regards as heartless sentences (4)
I believe the answer is:
sees
'regards' is the definition.
('see' can be a synonym of 'regard')
'heartless sentences' is the wordplay.
'heartless' says to hollow out the word (remove centre letters).
'sentences' with its middle removed is 'SEES'.
'as' acts as a link.
(Other definitions for sees that I've seen before include "Gets sight of" , "Dioceses; views" , "Watches" , "Observes the bishops' domains" , "Bishops' dioceses" .)