How do you say in Portuguese language be good?

There are a few ways to say "be good" in Portuguese, depending on the context and nuance you want to convey:

General "be good"

* Seja bom: This is the most direct and common way to say "be good."

* Esteja bem: This means "be well" and can be used as a polite farewell.

"Be good" as in "behave well"

* Seja um bom menino/uma boa menina: This literally translates to "be a good boy/girl." It is usually used for children.

* Porte-se bem: This means "behave well" and is more formal than the previous option.

"Be good" as in "be kind"

* Seja gentil: This translates to "be kind" and is a more positive and encouraging way to say "be good."

"Be good" as in "be well-behaved"

* Comporte-se: This means "behave yourself" and can be used in a more serious or authoritative tone.

The best way to choose the right phrase depends on the specific situation and your relationship with the person you're talking to.