It means: we are like inseparable mandarin ducks, looking forward to the harmony of a hundred years, the harmony of piano and harp.
The original text is as follows:
As a birthday present for my wife.
Li Ying [Tang Dynasty]
Xie Jia's birthday, sunny, bright, spring flowers.
Jinfeng is opposite to double jadeite, and Qin Shu has seven strings at the beginning.
When the mandarin ducks cross the neck, it will be a thousand years, and the harp will be a hundred years.
I should hate the guest who has not returned, and the green window is red and tears are cold.
Translation:
Your birthday, just like Xie An's niece Xie Daowen's birthday, coincides with a beautiful season, on a sunny and warm spring day in bloom.
Bird-shaped jewelry made of gold, silver and jade makes your appearance more charming, just like Zhuo Wenjun playing seven strings on the piano.
We are like inseparable mandarin ducks, looking forward to a hundred years of harmony.
At this moment, you should be complaining about me. You never came back from a foreign country and cried with lights and candles in the green screen window.