Lyrics:

Foolproof, that's what my heart's become
And I challenge anyone to break in
I challenge anyone to make me open up the door
'Cause I've been fooled before
And now I'm foolproof
Older and wiser now
And I'm never going to fall for that old
Never going to fall for that old
Fairytale any more
'Cause I've been schooled before
And 'cause I'm foolproof
And I dare anyone to try
Not a care in the world have I
As long as I am foolproof
Oh, no, they can't fool me
'Cause I've been around the block a few times
I've been around enough to know I'm
Coming back for more
'Cause I believe that your heart is pure
And 'cause I'm foolproof
Foolproof, that's what my heart's become