Confess to (3,2)
I believe the answer is:
own up
'confess to' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for own up that I've seen before include "Accept responsibility" , "be honest" , "Confess, admit guilt (3.2)" , "Come clean (about wrongdoing)" , "Admit to wrongdoing" .)