Hi Alex,
Could you check my English rendition?

Hi, Eldad!
"Eu não acho" means both "I don't think" and "I don't believe", so you can choose one. "Entenderia" is "futuro do pretérito", so it means "would understand". That's the only correction here.

Thank you very much. I wasn't sure - I'm glad I asked you.

E parabéns pelas outras traduções do português! Estive olhando algumas e me parecem excelentes! :)

I'm so glad to hear/read that!
It's a pleasure for me to translate your sentences. Afterwards I'll also render them in Hebrew.

What about Esperanto, Eldad? :)

Thanks, Alex.

"que ela entenderia" - should it be said only on something in the past?

Could you give me another example for the use of verbs in such construction/tense?

In English, you'll always use "WOULD + VERB":
=> Eu não FARIA isso se fosse você.
=> Eu não IRIA lá ainda que pudesse.
=> Nós não DIRÍAMOS nada nem sob tortura.
=> Eles nos CONTARIAM se soubessem de alguma coisa.

Thank you very much, Alex.
I'll now add your four sentences, together with English counterparts. I'd appreciate it if you can check them.

Here they are:

http://tatoeba.org/eng/sentences/show/1406025
http://tatoeba.org/eng/sentences/show/1406029
http://tatoeba.org/eng/sentences/show/1406040
http://tatoeba.org/eng/sentences/show/1406048