新婚快乐的英文是 "happy wedding" 或 "congratulations on your wedding". 来源于英语中的 "wedding"，意为婚礼。

例句：

"Congratulations on your wedding! Wishing you both a lifetime of happiness together." (新婚快乐！祝你们永远幸福。)

"Happy wedding! May your marriage be filled with love, laughter, and joy." (新婚快乐！愿你们的婚姻充满爱、欢笑和欢乐。)

"Wishing you both a happy and healthy marriage. Congratulations on your wedding!" (祝你们婚姻幸福健康。新婚快乐！)