Single pitch intended, we hear, to describe an act that will make amends (9)
I believe the answer is:
atonement
'amends' is the definition.
(atonement is a kind of amends)
'single pitch intended we hear' is the wordplay.
'single' becomes 'a'.
'pitch' becomes 'tone' (tone is a kind of pitch).
'intended' becomes 'meant' (to mean something is to intend it).
'we hear' shows a homophone (sound like).
'meant' sounds like 'ment'.
'a'+'tone'+'ment'='ATONEMENT'
'to describe an act that will make' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for atonement that I've seen before include "Compensation for a wrong" , "needed to make amends" , "Making good" , "reparations?" , "Making amends" .)