Key of G5 chords, Key of Bb5 . Capo 3.

 G5         E5          D5     C5
Don't be afraid, it's only love (x4)
        G5 - E5 - D5 - C5
Love is simple (x3)
 G5         E5          D5     C5
Don't be afraid, you're already dead (x4)
        G5 - E5 - D5 - C5
Love is simple.

I personally do the Same chord progression for the "da-da-da" part as well, but you 
figure another one out if you want. All I know is this matches the key of the recording of 
song. Ear training is how you do it.