O fato é importante.

O is the masculine singular definite article, so it means the.

It is used because fato is a singular masculine noun:

• o fato = the fact
• um fato = a fact

Because fato is grammatically masculine.

In Portuguese, nouns have grammatical gender, and the article must agree with the noun:

• o = masculine singular
• a = feminine singular

So:

• o fato
• but a coisa, for example

This is grammatical gender, not biological gender.

Because that is simply the gender assigned to the noun in Portuguese. In many cases, nouns ending in -o are masculine, and fato follows that common pattern.

That said, gender is something you usually learn together with the noun:

• o fato
• not just fato

É is the third-person singular form of the verb ser, which means to be.

So here:

• o fato = the subject
• é = is
• importante = important

This is the normal equivalent of is in The fact is important.

The accent is important for two reasons:

1. It shows the stressed vowel.
2. It distinguishes é from e.

Compare:

• é = is
• e = and

So the accent is not optional here.

Because importante is a predicate adjective: it describes the subject after the verb ser.

This is completely normal in Portuguese:

• O fato é importante.
• A ideia é boa.
• O carro é novo.

Here the structure is:

subject + verb + adjective

Some adjectives in Portuguese have the same form for masculine and feminine singular. Importante is one of them.

So you get:

• o fato é importante
• a questão é importante

The adjective only changes in the plural:

• os fatos são importantes
• as questões são importantes

In normal everyday Portuguese, that would usually sound unnatural in this context.

With a countable noun like fato, Portuguese normally wants an article:

• O fato é importante.

Without the article, it might sound like a headline, a very compressed style, or an unusual abstract statement. For a learner, use the article here.

Usually, no.

Use ser when you are describing something as a general or essential characteristic:

• O fato é importante.

Use estar for a temporary state or condition.

So:

• é importante = it is important
• está importante would sound strange in most contexts

For this sentence, é is the natural choice.

A rough pronunciation for an English speaker is:

u FA-tu eh im-por-TAN-tchi

A few helpful notes:

• o by itself often sounds like u in Brazilian Portuguese
• the final -o in fato is often pronounced like u
• é sounds like eh
• the final -e in importante often sounds like -i
• in many Brazilian accents, te sounds like tchi

A more careful approximation is:

u FA-tu EH im-por-TAN-tchi

In Brazilian Portuguese, the normal spelling is fato.

In European Portuguese, you will often see facto.

So if you are learning Brazilian Portuguese, fato is the form you should use.

Yes. It is a very common and useful pattern:

article + noun + ser + adjective

You can reuse it with many words:

• O livro é interessante.
• A casa é grande.
• O problema é sério.
• A resposta é correta.

So O fato é importante is a good model sentence for basic Portuguese grammar.