Cheat ultimately regrets hesitations, means to stop lying (5,5)
I believe the answer is:
truth serum
'stop lying' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe you can see a link between them that I don't see?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for truth serum that I've seen before include "that should get you talking!" , "means to get whoppers out" .)