Only Czechs would bring the word death into a happy ending :-)
In German (Grimm original) this phrase is "Und wenn sie nicht gestorben sind, dann leben sie noch heute", which means "and if they haven't died they are still living today". Nothing about happiness (though it is implied by context). :-)
In czech we have another phrase 'A jestli neumřeli, žijí tam do dnes.'
You can find similar phrasing in English translations of the Grimm brothers or in The Book of the Thousand Nights and One Night and probably in many more occasions.