人无千日好: Literal Translation Is Completely Different
It's an old Chinese proverb, that's why there are some words missing.

In old times, as long as people can understand what you mean, you can omit as many as words you want.

The whole sentence is


  人无千日好，花无百日红。


Here, 好 means happy, happy life, good life, or easy life.

And 百, 千, 万 in Chinese proverbs or idioms usually refers to a very long time

So the whole sentence's meaning is:


  There is no person can be happy for a thousand days, and there is no flower can bloom for a hundred days.


which means:


  Someone is happy for now doesn't mean he can be happy forever.


it also means:


  Someone (maybe your friend) is nice to you now doesn't mean he can be nice to you forever.


it's like the proverb in English:


  For age and want save while you may; no morning sun lasts a whole day