Following are a number of back-translations as well as a sample translation for translators of Proverbs 14:13:

• Kupsabiny: “You may laugh even when mourning,
  after that, you cry again.” (Source: Kupsabiny Back Translation)
• Newari: “A cheerful face can conceal a sad heart,
  but rejoicing can turn to sorrow.” (Source: Newari Back Translation)
• Hiligaynon: “You (sing.) can-possibly hide your (sing.) sadness in your (sing.) laughter, but after you (sing.) have-finished laughing the sadness is still there.” (Source: Hiligaynon Back Translation)
• Kankanaey: “Even though a person is smiling/laughing, it is possible that he is sorrowing nonetheless. Happiness can result/end-up in sorrow.” (Source: Kankanaey Back Translation)
• English: “Sometimes when people laugh, they are really sad,
  and when they stop laughing, they are still sad.” (Source: Translation for Translators)