Puedes ser cortes

[hola]

there is an ongoing debate as to how to correctly say you can be polite when you want to

at first i thought it was puedes ser cortes cuando quieres
then i found out it was puede estas cortes cuando quieres

another spanish expert actually told me both were right
i know he has to be wrong even though he is an expert

i can understand why one would think it's written w/ ser
i can also understand why one would think it's written w/ esta

the spanish word for be or to be is ser

[Tomisimo]

Who told you it should use estar? It should be "Puedes ser cortés cuando quieras".

[hola]

i knew it! thank you diamond

[Tomisimo]

Originally Posted by hola

i knew it! thank you diamond

But do you know why it needs to be ser?

[geeper]

Quiero saber por qúe, por favor.

[CrOtALiTo]

It were right.

It in the second chose, it would be Puedes ser cortes cuando quieras.

So it's right.

[barrenfield]

so why does it need to be "ser"? sandy

[Rusty]

Ser is used when you're describing someone's permanent or definitive characteristics (even if the latter aren't permanent). Being courteous is definitive, just as being new at something is definitive (you won't always be new at something, but until you aren't, this describes that characteristic and it requires ser).

There is a thread stuck at the top of the grammar forum that describes when to use ser and when to use estar. I found some of the words I used above in that post.

[sosia]

The usual way, as explained above, its "eres". "To be polite" it's "ser educado"
-Eres muy cortés
-Juan es un joven muy cortés.
-Puedes ser cortés cuando quieres.

You can use "estar", but only when it means a momentary status, like "cuando quieres, estás muy cortés"
Here is an irony inside, you're actually saying he is usually not polite, but he is being polite now due to interest.
You can say "cuando quieres, eres muy cortés", wich is the usual ironic way, but saying it "estar" you say the same but you're more wicked as usual.

About the sentences:
-puedes ser cortés cuando quieres
-puedes estar cortés cuando quieres , but only in wicked times
I´m with your spanish expert

Saludos