Push me down
and I'll grow.
Confess our secret
and I'll go.

I am the one
that hides within
the silencer known
as the guillotine.

I punish the
ones with heart
and strip away
their mirth.

Only talk to me
if you are insane.
I'm dangerous, but
clearly not inane.

Who am I?

Hint 1

I am a form e when set in motion.

Hint 2

I lay concealed in another form in the title