A descrição do pertence mostra a localização.

Do is the contraction of de + o:

• de = of
• o = the

So:

• do pertence = of the pertence

This kind of contraction is extremely common in Portuguese:

• de + a = da
• de + os = dos
• de + as = das

Examples:

• a cor do carro = the color of the car
• a porta da casa = the door of the house

Because both nouns are feminine in Portuguese:

• a descrição
• a localização

In Portuguese, every noun has a grammatical gender, and the article has to match it.

A few patterns that may help:

• Nouns ending in -ção are usually feminine:
  • a descrição
  • a localização
  • a informação
  • a tradução

So the sentence uses a because both of those nouns are feminine singular.

Because the subject is singular:

• A descrição do pertence = the subject
• mostra = shows

The head of the subject is descrição, which is singular, so the verb must also be singular.

Compare:

• A descrição do pertence mostra a localização.
  = The description of the belonging/item shows the location.

• As descrições dos pertences mostram a localização.
  = The descriptions of the belongings/items show the location.

Even though there are several words before the verb, the verb agrees with descrição, not with the noun inside the de phrase.

Here, pertence is being used as a noun, not as the verb pertencer.

As a noun, pertence can mean something like:

• belonging
• possession
• personal item

However, native speakers more often use the plural pertences to mean belongings.

So while o pertence is understandable in some contexts, it can sound a bit unusual by itself. Depending on the situation, more natural alternatives might be:

• A descrição do item mostra a localização.
• A descrição do objeto mostra a localização.
• A descrição dos pertences mostra a localização.

So a learner might want to remember:

• pertence can be a noun
• but pertences is much more common in everyday Portuguese

Yes. Pertence can also be the he/she/it form of the verb pertencer:

• Isso pertence a Maria.
  = That belongs to Maria.

So Portuguese learners may notice an ambiguity:

• pertence as a verb = belongs
• pertence as a noun = belonging / possession

In your sentence, it is a noun, because it comes after do and functions as part of the noun phrase a descrição do pertence.

Portuguese uses articles more often than English does.

In this sentence:

• A descrição
• a localização

English might sometimes say something like Description shows location in a label or interface, but Portuguese usually sounds more natural with the article:

• A descrição mostra a localização.

This is very common in standard Portuguese. Articles often appear before nouns even when English leaves them out.

Yes, the basic structure is natural and follows a common pattern:

• A descrição do pertence = subject
• mostra = verb
• a localização = object

So the order is:

Subject + Verb + Object

Very similar to English:

• The description of the item shows the location.

The phrase do pertence is attached to descrição, explaining what description we are talking about.

More or less, yes:

• A = the
• descrição = description
• do = of the
• pertence = belonging / item
• mostra = shows
• a localização = the location

So a literal version would be:

The description of the belonging shows the location.

But literal translations are not always the most natural English, and the Portuguese itself may also sound a little unusual because of pertence in the singular. In many contexts, item or object would sound more natural in English and Portuguese.

They might in a very specific or technical context, but for many learners this phrase will sound a bit unusual.

More natural possibilities often include:

• do item
• do objeto
• dos pertences (if talking about belongings in general)

So if you saw this in an app, label, or machine-translated text, it might be grammatically possible but not the most idiomatic everyday wording.

Localização usually means location in a more formal or precise sense.

Compare:

• localização = location / positioning
• lugar = place
• local = place / site / location, depending on context

Examples:

• A localização do carro = the location of the car
• Que lugar é esse? = What place is this?
• Este é o local da reunião. = This is the location/site of the meeting.

In your sentence, localização fits well because it sounds like the sentence is talking about where something is located.

A rough pronunciation guide is:

a des-kree-SAW do pehr-TEN-see MOSS-tra a lo-kah-lee-zah-SAW

A few notes:

• descrição ends with a nasal sound: -ção
• localização also ends with -ção
• In Brazilian Portuguese, ção sounds roughly like saw̃ (nasalized)

A more IPA-style version would be approximately:

[a dʒiskɾiˈsɐ̃w du peʁˈtẽsi ˈmɔstɾa a lowkalizaˈsɐ̃w]

Exact pronunciation varies by region, but that gives you a good Brazilian Portuguese starting point.