Sy vra waarna ek soek.

It has two parts:

• Sy vra = the main clause
• waarna ek soek = an indirect question, functioning as the object of vra

So the sentence is built like:

• She asks
  • what I am looking for

Afrikaans often uses this kind of structure after verbs like vra.

Waarna is the standard Afrikaans form used when a preposition is linked to what for a thing, idea, or action.

Here it contains the preposition na, which goes with soek na = look for.

So:

• na = for / after
• waarna = what ... for / for what

English usually leaves the preposition later in the clause, as in What are you looking for?
Afrikaans usually pulls it into one word at the front: Waarna soek jy?

Because waarna ek soek is a subordinate clause, specifically an indirect question.

In Afrikaans subordinate clauses, the finite verb normally goes to the end.

Compare:

• Direct question: Waarna soek ek?
• Indirect question: Sy vra waarna ek soek.

That final position for soek is completely normal in this kind of clause.

Because this is not a direct question. It is an indirect question inside a larger sentence.

In a direct question, Afrikaans usually has inversion:

• Waarna soek jy?

In an indirect question, the subject comes before the verb:

• Sy vra waarna ek soek.

So:

• direct question: question word + verb + subject
• indirect question: question word + subject + verb

Afrikaans does not usually mark the continuous tense the way English does.

So ek soek can mean:

• I look
• I am looking

The context tells you which one is meant. In this sentence, English naturally translates it as I am looking for, but Afrikaans simply uses soek.

The same is true for vra:

• sy vra can mean she asks or she is asking, depending on context.

Sometimes yes, because soek can also take a direct object:

• Ek soek my sleutels = I am looking for my keys

So wat ek soek can also make sense as what I am looking for.

However, waarna is the natural choice when you are using the soek na pattern and especially when the question word includes that preposition. In standard Afrikaans, forms like waarna, waarvoor, waarmee, waarin are very common and important.

So Sy vra waarna ek soek is a very normal and idiomatic sentence.

Because of its position and function in the sentence.

In Sy vra, sy is clearly a subject pronoun before a verb, so it means she.

When sy means his, it is possessive and normally comes before a noun:

• sy boek = his book
• sy motor = his car

So here:

• Sy vra = She asks

Yes. This is a very common Afrikaans pattern.

Some useful examples are:

• waarmee = with what
• waarvoor = for what
• waarin = in what
• waarop = on what
• waaroor = about what
• waarvan = of what / from what
• waartoe = for what purpose / to what

These are especially common when English would put the preposition at the end:

• What are you talking about? → Waaroor praat jy?
• What are you writing with? → Waarmee skryf jy?
• What are you waiting for? → Waarvoor wag jy?

So learning waarna helps you learn a whole Afrikaans pattern.