Die huwelik is gelukkig.

Here die means the.

A few useful points:

• It is pronounced roughly dee, not like English die.
• Afrikaans uses die as the definite article for singular and plural nouns.
• It does not change for grammatical gender.

In this sentence it is capitalized only because it is the first word. In the middle of a sentence, it would normally be die.

Usually huwelik means marriage: the state or institution of being married.

If you specifically mean the wedding ceremony, Afrikaans often uses troue instead.

So Die huwelik is gelukkig is most naturally understood as The marriage is happy, not The wedding is happy.

Afrikaans and English are both Germanic languages, so some words look similar.

But there is also an important grammar point: in Afrikaans, is is used much more widely than English is. In the present tense, you say:

• ek is = I am
• jy is = you are
• hy/sy is = he/she is
• ons is = we are
• hulle is = they are

So Afrikaans does not have separate present-tense forms like am / is / are.

Because gelukkig is a predicate adjective here. It comes after the linking verb is, just like in English:

• The marriage is happy
• Die huwelik is gelukkig

It is not being used directly before the noun. If it were, you would get a different structure, such as die gelukkige huwelik = the happy marriage.

This is a very common Afrikaans adjective pattern.

• After a linking verb like is, the adjective usually stays in its basic form: gelukkig
• Before a noun, the adjective often takes -e: gelukkige

So:

• Die huwelik is gelukkig = The marriage is happy
• die gelukkige huwelik = the happy marriage

That is why gelukkige would sound wrong in your original sentence.

Yes. Gelukkig can have more than one use.

In your sentence, after is, it means happy or fortunate as an adjective.

But it can also be used more like fortunately, often applying to the whole sentence, for example:

• Gelukkig was niemand beseer nie. = Fortunately, nobody was injured.

So the meaning depends on how it is used in the sentence.

The basic order is:

subject + verb + complement

So here:

• Die huwelik = subject
• is = verb
• gelukkig = complement/adjective

This is very similar to English.

Two useful comparisons:

• Statement: Die huwelik is gelukkig.
• Yes/no question: Is die huwelik gelukkig?

You say:

Die huwelik is nie gelukkig nie.

Afrikaans commonly uses a double nie in negation:

• the first nie usually comes after the verb or the part being negated
• the second nie usually comes near the end of the clause

So this is a classic Afrikaans pattern and one worth memorizing early.

You simply move the verb to the front:

Is die huwelik gelukkig?

This is the normal yes/no question pattern in Afrikaans.

So:

• Statement: Die huwelik is gelukkig.
• Question: Is die huwelik gelukkig?