SOURCE: Stutchkoff, Der Oytser fun der Yidisher Shprakh. Onion tears, like crocodile tears, are not true expressions of sadness. (Why do onions make you cry?) Compare:
Tsibele-trern rirn nit dos harts. | .ציבעלע–טרערן רירן ניט דאָס האַרץ
Onion tears don't touch the heart.
SOURCE: Stutchkoff, Der Oytser fun der Yidisher Shprakh