Isso é verdadeiro.

Isso means that or this thing in a general, neutral sense.

In Isso é verdadeiro, isso is a demonstrative pronoun pointing to some idea, statement, or situation that was just mentioned.

Examples:

• Isso é importante. = That is important.
• Isso é verdade. = That is true.

In Brazilian Portuguese, isso is very common when referring to something the other person said or something already being discussed.

Both isso and isto can mean something like this/that, but in modern Brazilian Portuguese, isso is much more common in everyday speech.

A very simplified way to think about it:

• isto = this
• isso = that
• aquilo = that over there / that thing

But in real Brazilian usage, isto is often avoided in normal conversation, and isso frequently does the job.

So even if a learner expects isto for this, Brazilians will often naturally say isso instead.

É is the third-person singular form of the verb ser (to be):

• eu sou
• você é
• ele é
• isso é

The accent is important because:

• é = is
• e = and

So:

• Isso é verdadeiro. = That is true.
• Isso e verdadeiro. would be incorrect.

Verdadeiro is an adjective, meaning true.

It changes form depending on gender and number:

• verdadeiro = masculine singular
• verdadeira = feminine singular
• verdadeiros = masculine plural
• verdadeiras = feminine plural

In this sentence, it is masculine singular because it is describing isso, which is treated as masculine singular in this kind of structure.

Because isso is grammatically treated as masculine singular.

Even though isso refers to an idea or statement rather than a masculine object, Portuguese still uses masculine singular agreement here:

• Isso é verdadeiro.
• Isso é falso.
• Isso é bom.

So the adjective matches isso, not the English idea behind it.

It is grammatical and understandable, but it can sound a bit formal or less common in everyday conversation.

In many situations, Brazilians are more likely to say:

• Isso é verdade.
• É verdade.
• Isso é verdade mesmo.

Why? Because verdade as a noun is very commonly used in this expression:

• É verdade. = It’s true.
• Isso é verdade. = That’s true.

So Isso é verdadeiro is not wrong, but Isso é verdade often sounds more natural in daily speech.

They are very close in meaning, but they are built differently:

• Isso é verdadeiro.
  Literally: That is true.
  Here, verdadeiro is an adjective.

• Isso é verdade.
  Literally: That is truth / more naturally That is true.
  Here, verdade is a noun.

In practice, Isso é verdade is usually the more idiomatic everyday choice in Brazilian Portuguese.

Yes, very often.

É verdade is extremely common and natural when the context already makes it clear what you are talking about.

Examples:

• A: O filme foi cancelado.
• B: É verdade? = Is that true?

or

• A: Ele já chegou.
• B: É verdade. = That’s true.

So if the topic is already clear, you do not need to include isso.

The normal order is:

Isso + é + verdadeiro

This is the standard and most neutral order.

You usually would not rearrange it in ordinary speech. Portuguese does allow flexible word order in some cases, but for a basic statement like this, keeping the usual order is best.

So learners should stick with:

• Isso é verdadeiro.

A rough pronunciation guide for English speakers is:

EE-so eh vehr-dah-DAY-roo

A few notes:

• Isso: the ss sounds like the s in see, not like z
• é: a clear open vowel, like eh
• verdadeiro: stress falls on dei: ver-da-DEI-ro

A more approximate Brazilian pronunciation in syllables:

• IS-so é ver-da-DEI-ro

Yes, in many contexts.

If the meaning is already obvious, Portuguese often says:

• É verdade.
• É verdadeiro. (less common, depending on context)

But if you want to point specifically to something that was said or shown, isso helps make the reference clear:

• Isso é verdade.
• Isso é verdadeiro.

So isso is optional only when context already does the work.

Yes, verdadeiro can describe many kinds of nouns.

Examples:

• uma história verdadeira = a true story
• um amigo verdadeiro = a true/genuine friend
• um fato verdadeiro = a true fact

So in Isso é verdadeiro, it describes the statement or idea as being true.

Depending on context, verdadeiro can mean:

• true
• real
• genuine

Usually verdade is the most natural choice for that’s true:

• Isso é verdade.
• É verdade.

Certo can mean right/correct, but it is not always the same as true.

Compare:

• Isso é verdade. = That is true.
• Isso está certo. = That is correct / That is right.

So if you want the exact idea of factual truth, verdade or verdadeiro fits better than certo.