"Ach, wie ist's möglich dann" also known as "Treue Liebe" (True/Loyal Love), and “How Can I Leave Thee” is a German now-traditional song.
[4] The silent film Ach, wie ist's möglich dann (1913) by Peter Ostermayr bears the song's title.
Du hast das Herze mein so ganz genommen ein, dass ich kein and're lieb' als dich allein.
If I were a little bird, I would soon be with you, not afraid of falcon or hawk, I would fly quickly to you; if a hunter should shoot me dead, I would fall onto your lap; if you would behold me sadly, I would gladly die.
Falcon nor hawk would fear, Speeding to thee; When by the fowler slain, I at thy feet should lie, Thou sadly shouldst complain, Joyful I'd die.