Lyrics:

Revenge must be the reason
Why forgiveness was a thing I never knew
And someday soon I know you plan to hurt me
But don't plan on getting by with the things you do

'Cause I'll always know when you been cheating
And I'll always know when you've been untrue
I'll always know

Your heart is like a window
When I look inside I see another man
But go on and lie and tell him how you fooled me
But remember I saw through your evil plan

And I'll always know when you been cheating
Yeah, I'll always know when you've been untrue
I'll always know and don't forget it either