I Believe ~Yume wo Kanaeru Mahou no Kotoba~ / Don't leave me (I Believe 〜夢を叶える魔法の言葉〜 / Don't leave me) is a collaboration single by Minami Akina no Super Mild Seven, Satoda Mai, and Gouda Kazoku. It was released on June 17, 2009, reaching position #4 on the Oricon Weekly chart and selling a total of 47,798 copies. "I Believe ~Yume wo Kanaeru Mahou no Kotoba~" and "Don't leave me" appear on the We Love Hexagon 2009 album, "Don't leave me" also appears on the Satoda Mai with Gouda Kazoku album.