Die stembrief is vertroulik.

Here die means the.

A useful thing to know is that Afrikaans uses die as the definite article for all nouns:

• singular
• plural
• all genders

So unlike languages such as German or Dutch, you do not have to learn different forms like the for masculine, feminine, or neuter nouns.

In this sentence:

• die stembrief = the ballot / the ballot paper

Also, die is usually pronounced like dee, not like the English word die.

Because Afrikaans normally writes compound nouns as one word.

So:

• stem = vote
• brief = letter / written document

Together, stembrief is a fixed compound meaning ballot or ballot paper, not a literal vote letter in normal English.

This is very common in Afrikaans:

• stemlokaal = polling station
• stemdag = election day
• stemreg = voting right / suffrage

If two words function as one noun idea, Afrikaans often joins them.

Vertroulik is an adjective here.

It describes the noun stembrief:

• Die stembrief is vertroulik.
• The ballot is confidential.

After is, the adjective is acting as a predicate adjective: it tells you what the subject is like.

So the structure is:

• Die stembrief = subject
• is = verb
• vertroulik = adjective complement

Because after is, Afrikaans usually uses the base form of the adjective.

Compare:

• Die stembrief is vertroulik.
  The ballot is confidential.

But before a noun, the adjective usually takes -e:

• die vertroulike stembrief
  the confidential ballot

So:

• after is → vertroulik
• before a noun → vertroulike

That is a very common Afrikaans pattern.

Is is the present-tense form of to be.

It links the subject to a description:

• Die stembrief → the ballot
• is vertroulik → is confidential

One nice feature for English speakers is that Afrikaans does not change this verb in the present tense the way English does:

• Ek is = I am
• Jy is = you are
• Hy is = he is
• Ons is = we are
• Hulle is = they are

So is is used with all persons.

Yes, in this simple statement it is very similar to English.

The pattern is:

• Subject + verb + complement
• Die stembrief + is + vertroulik

That matches:

• The ballot + is + confidential

So this sentence is a good example of a very straightforward Afrikaans main clause.

You would normally use the Afrikaans double nie pattern:

• Die stembrief is nie vertroulik nie.
• The ballot is not confidential.

This is one of the most important Afrikaans grammar points.

The pattern is often:

• subject + verb + nie
  • rest + nie

So here:

• Die stembrief = subject
• is = verb
• nie vertroulik nie = not confidential

A simple learner-friendly pronunciation guide would be:

• Die → dee
• stembrief → roughly stem-breef
• is → iss
• vertroulik → roughly fer-TROW-lik or ver-TROW-lik

A few notes:

• ee in brief sounds like the vowel in see
• ou in vertroulik sounds roughly like the vowel in house
• the r may be rolled or tapped, depending on accent

So the whole sentence is approximately:

dee stem-breef iss fer-TROW-lik

No, not in the way many European languages do.

In this sentence, die does not tell you anything about masculine, feminine, or neuter gender. Afrikaans has mostly lost grammatical gender distinctions in everyday article use.

So you do not need to memorize different words for the depending on the noun’s gender. That makes sentences like this much easier to build.

You can use the parts to help remember it, but you should translate the whole compound naturally.

So:

• stem helps you think of voting
• brief helps you think of a written document

But the natural meaning of the whole word is:

• ballot
• ballot paper

That is an important habit in Afrikaans: compounds are often understandable by parts, but the best translation is usually the meaning of the whole word, not a word-for-word English version.