新婚愉快的英文表达是 "happiness in marriage" 或 "happy marriage". 这个短语来源于人们对新婚夫妇祝愿幸福美满的婚姻生活。下面是一些英文例句及其中文翻译：

May your marriage be filled with love, laughter, and happiness. (愿你们的婚姻充满爱、欢声笑语和幸福。)

We wish you a long and happy marriage. (我们祝愿你们结一段长久幸福的婚姻。)

Congratulations on your happy marriage! (恭喜你们幸福的婚姻！)

We hope that your marriage is filled with love and happiness. (我们希望你们的婚姻充满爱和幸福。)