Certamente ele vai chegar.

In Brazilian Portuguese, ir + infinitive is extremely common for talking about the future.

So:

• ele vai chegar = he is going to arrive / he will arrive
• ele chegará = also he will arrive

The difference is mostly about style and frequency:

• vai chegar sounds more natural in everyday speech
• chegará sounds more formal, written, or literary

So this sentence uses the future form that Brazilians are very likely to say in conversation.

Certamente means something like:

• certainly
• definitely
• for sure

It adds confidence or certainty to the statement. The speaker is not just saying that he will arrive, but that they are quite sure about it.

Yes, it is correct and natural, but it can sound a little more formal or polished than some everyday alternatives.

In casual speech, Brazilians often say:

• com certeza
• claro
• sem dúvida

So:

• Certamente ele vai chegar. = correct, natural, somewhat more formal
• Com certeza ele vai chegar. = very common in speech

Yes. Adverbs like certamente can often move around.

These are all possible:

• Certamente ele vai chegar.
• Ele certamente vai chegar.
• Ele vai certamente chegar.

The most natural choices are usually:

• Certamente ele vai chegar
• Ele certamente vai chegar

The version with certamente between vai and chegar is grammatical, but often feels a bit less natural in everyday speech.

Sometimes yes.

Portuguese often allows the subject to be omitted when it is clear from context. So you may hear:

• Certamente vai chegar.

That means He will certainly arrive, if everyone already knows who is being talked about.

However, in Brazilian Portuguese, subject pronouns are used more often than in European Portuguese, so keeping ele is very normal.

Because Portuguese uses the pattern ir + infinitive directly.

So:

• vai chegar
• literally: goes arrive
• naturally: is going to arrive / will arrive

English needs to in going to arrive, but Portuguese does not add anything between vai and chegar.

Usually yes, in a sentence like this by itself.

But grammatically, ele can also refer to a masculine noun already mentioned, so in some contexts it could mean it.

For example:

• O ônibus? Ele vai chegar logo.
• The bus? It will arrive soon.

So ele is not always a male person, but without context, learners will normally understand it as he.

A useful approximate pronunciation is:

• chegar ≈ sheh-GAR (with the stress on the last syllable)

A few details:

• ch in Brazilian Portuguese sounds like English sh
• the final r is not the strong English r
• in many Brazilian accents, the final r sounds more like a soft h sound

So depending on accent, it may sound roughly like:

• sheh-GAH
• or sheh-GAR with a light final sound

A rough pronunciation guide is:

Certamente ele vai chegar
≈ sehr-tah-MEN-chee EH-lee vai sheh-GAR

A few notes:

• certamente has stress on men
• ele is usually EH-lee
• vai sounds like the English word vie
• chegar begins with sh

Depending on region, the exact sounds can vary a bit.

Often yes, but in Portuguese this structure is even broader than in English.

Vai chegar can mean:

• is going to arrive
• will arrive

In English, is going to sometimes emphasizes a planned or expected future. In Portuguese, vai + infinitive is simply one of the main normal ways to talk about the future, even when there is no strong sense of planning.

No, not by itself.

Certamente ele vai chegar expresses confidence that he will arrive.

It does not mean:

• he must be arriving = more like a deduction about what is happening now
• he should arrive = could express expectation or obligation

For those meanings, Portuguese would usually use different wording, such as:

• Ele deve estar chegando. = He must be arriving / He is probably arriving
• Ele deve chegar. = He should arrive / He is expected to arrive

So vai chegar is a straightforward future form.