Como dizer "Nem tudo são flores" em inglês

Hi BiahCane!

Suggestion:

"Life is not a bed of roses"

Sugestão:

Not always a bed of roses

He soon discovered that living in a foreign country is not always a bed of roses. - Thefredictionary

I never promised you a rose garden.
No one ever promised you a rose garden.

Sugestão:
Not everything is good

Tem outro ditado semelhante "not everything that shine is gold"

Getting married is amazing and fun, that is what comes after the “I dos” and it is not always a cakewalk. One workaround way to say that "depois de casados nem tudo são flores/nem tudo é fácil.
That applies to everything, a new job, going to the university, etc.

There are also the "who loves roses will endure the thorns". (since roses almost always have thorns), plus "it goes with the territory" or still "no pain no gain", depending on the context. We know that life is not always smooth sailing...sometimes we hit a rough patch/a bump as well.