Greek has an adjective
ἀνυπόκριτος that has been translated as unfeigned or
genuine.
If
this word was translated literally it might be unactorly or not
dramatically or by a phrase not like a stage performer or actor or
even unmasked since actors and performers in Greek and Roman Dramas
wore masks.
Here's
a quote that includes that word.
Romans
12:9 ἡ ἀγάπη ἀνυπόκριτος
Let
love be genuine or in some older versions unfeigned is used.
Love
Agape must be an sincere action not an act.
This
word is also used again in 2 Corinthians 6.6