Este perfume tem um cheiro bom.

Este means this.

In traditional grammar:

• este = this (near the speaker)
• esse = that (near the listener or already mentioned)
• aquele = that over there

In everyday Brazilian Portuguese, though, esse is often used where careful grammar would use este. So Este perfume tem um cheiro bom is correct, but Esse perfume tem um cheiro bom is also very common in Brazil.

Because perfume is a masculine noun in Portuguese: o perfume.

So the demonstrative has to match it:

• este perfume
• not esta perfume

This is something learners often have to memorize, because noun gender in Portuguese does not always match the word ending. Even though perfume ends in -e, it is masculine.

Here, Portuguese is using a very natural structure that literally means has a good smell:

• tem = has
• um cheiro bom = a good smell / a nice scent

So the sentence is literally This perfume has a good smell, even though the English meaning may simply be This perfume smells good.

Portuguese often expresses ideas this way. It is idiomatic and natural.

Yes. Este perfume cheira bem is a very good alternative and means This perfume smells good.

A few natural options are:

• Este perfume tem um cheiro bom.
• Este perfume cheira bem.
• Este perfume é cheiroso.

They are all correct, but they feel slightly different:

• tem um cheiro bom = describes the perfume as having a pleasant scent
• cheira bem = more directly smells good
• é cheiroso = is fragrant / smells nice

Um is the indefinite article, meaning a/an.

So:

• um cheiro bom = a good smell / a nice scent

In this sentence, tem um cheiro bom sounds very natural. You may also hear tem cheiro bom, but tem um cheiro bom feels fuller and more standard in this kind of statement.

In Portuguese, adjectives often come after the noun.

So the normal order is:

• cheiro bom = good smell

Putting the adjective before the noun is sometimes possible, but it can sound more literary, emphatic, or less natural in everyday speech. In this sentence, um cheiro bom is the usual order.

Because bom agrees with cheiro, and cheiro is masculine singular.

So:

• um cheiro bom
• not uma cheiro boa

If the noun were feminine, the adjective would change:

• uma fragrância boa

Portuguese adjectives usually agree in gender and number with the noun they describe.

They are not the same word.

• perfume = the perfume itself, the product
• cheiro = smell / scent

So in Este perfume tem um cheiro bom, the perfume is the thing, and cheiro is the scent it has.

That is why the sentence is structured like:

• This perfume
  • has
    • a good smell

Not always, but it often feels neutral or pleasant in everyday Brazilian Portuguese.

If you want to make it clearly negative, people often say:

• mau cheiro = bad smell
• cheiro ruim = bad smell

Also, odor exists, but it often sounds more formal and can feel more negative or technical than cheiro.

So cheiro bom is a very natural way to say a nice smell.

Yes, it is natural and fully correct.

That said, in casual Brazilian Portuguese, many people might be more likely to say:

• Esse perfume cheira bem.
• Esse perfume é cheiroso.

Also, esse is often more common than este in ordinary conversation. So your sentence is good Portuguese, but it may sound a bit more careful or textbook-like than the most casual spoken version.

In Brazilian Portuguese, tem is not pronounced like English tem with a clear final m sound.

The m at the end makes the vowel nasal. So it sounds roughly like:

• teh̃y / tẽj̃

The important point is:

• the vowel is nasal
• the final m is not strongly pronounced like in English

This is also why tem can be tricky for English speakers at first.

If the subject becomes plural, the verb changes too:

• Este perfume tem um cheiro bom.
• Estes perfumes têm um cheiro bom.

Notice:

• tem = singular
• têm = plural

The plural form has a written accent: têm.

You could also say:

• Esses perfumes cheiram bem.

That is another very natural plural version.