My interpretation is this: Those with a guilty conscience will confess their sins on judgment day. Not reluctantly, but willingly, eager to get the weight of their sins off their shoulders.
That those who carry dark secrets and hidden sins throughout their days will be very willing to unburden themselves when they are at the end of their life. The joy of letting the secrets go will be uplifting. She is also making the point that those who carry around hidden guilt live in a type of personal hell until they do unburden themselves.