Formal:
* At nagkaroon sila ng masayang buhay magpakailanman. (This is the most literal translation, emphasizing "happy life")
* At nabuhay silang maligaya magpakailanman. (This is another literal translation, emphasizing "happily lived")
Informal:
* At nagtapos sila ng masaya at maligaya. (This emphasizes the happy ending)
* At nabuhay sila nang masaya at maayos. (This emphasizes the happy and peaceful life)
* At naging masaya sila habang buhay. (This emphasizes the lasting happiness)
More poetic:
* At sila'y nagsama ng masaya magpakailanman. (This uses a more poetic and traditional phrasing)
* At naging ganap ang kanilang kaligayahan. (This emphasizes the fulfillment of their happiness)
Ultimately, the best translation depends on the context and the specific tone you want to achieve.