(元のウェブサイトはこちら)

1. Oh, don't play with my heart! Don't do that again. If you break it apart - I cannot be your friend

2. I won't mess with your head
  I won't play with your heart
  'Cause I'm a real girl
  I finish what I start.

(人の)感情をもてあそぶ)

Play with (her/my/your/...) heart/emotions/affections

3. Why does he play with my emotions?

(元のウェブサイトはこちら)