The word(s) "happy" appears 3 time(s) in 3 verse(s) in Quran in Abdullah Yusuf Ali translation.

(1) Then those who have believed and worked righteous deeds, shall be made happy in a Mead of Delight.

(سورة الروم, Ar-Room, Chapter #30, Verse #15)
(Arabic, Transliteration, Urdu (Ahmed Ali), Urdu (Jalandhry), Farsi, Yusuf Ali, Shakir, Picthal, Mohsin Khan, French, Spanish, Indonesian, Malay, German, Bosnian, Russian, Dutch, Italian, Portuguese, Tafsir - Jalal ad-Din, Tafsir - King Fahad Quran Complex)

(2) There was, for Saba, aforetime, a Sign in their home-land - two Gardens to the right and to the left. "Eat of the Sustenance (provided) by your Lord, and be grateful to Him: a territory fair and happy, and a Lord Oft-Forgiving!

(سورة سبإ, Saba, Chapter #34, Verse #15)
(Arabic, Transliteration, Urdu (Ahmed Ali), Urdu (Jalandhry), Farsi, Yusuf Ali, Shakir, Picthal, Mohsin Khan, French, Spanish, Indonesian, Malay, German, Bosnian, Russian, Dutch, Italian, Portuguese, Tafsir - Jalal ad-Din, Tafsir - King Fahad Quran Complex)

(3) But those who reject Our Signs, they are the (unhappy) Companions of the Left Hand.

(سورة البلد, Al-Balad, Chapter #90, Verse #19)
(Arabic, Transliteration, Urdu (Ahmed Ali), Urdu (Jalandhry), Farsi, Yusuf Ali, Shakir, Picthal, Mohsin Khan, French, Spanish, Indonesian, Malay, German, Bosnian, Russian, Dutch, Italian, Portuguese, Tafsir - Jalal ad-Din, Tafsir - King Fahad Quran Complex)