Ek is seker dat my ma reeds by die stasie is.

Dat means that and introduces a subordinate clause: dat my ma reeds by die stasie is.

So the sentence structure is:

• Ek is seker = I am sure
• dat ... = that ...
• my ma reeds by die stasie is = my mother is already at the station

In English, that is often optional, but in Afrikaans dat is very commonly used in sentences like this.

Because dat creates a subordinate clause, and in Afrikaans the finite verb usually goes to the end of a subordinate clause.

So:

• Main clause: My ma is reeds by die stasie.
• Subordinate clause after dat: dat my ma reeds by die stasie is

This is one of the most important word-order differences between English and Afrikaans.

They belong to two different clauses.

• Ek is seker = first clause
• dat my ma reeds by die stasie is = second clause

So the first is goes with ek, and the second is goes with my ma.

English also has two forms of to be here:

• I am sure
• that my mother is already at the station

Afrikaans just happens to use the same form, is, in both places.

Reeds means already.

It is correct and natural, but it can sound a little more formal or written than al, which is also very common in everyday Afrikaans.

So these are both possible:

• Ek is seker dat my ma reeds by die stasie is.
• Ek is seker dat my ma al by die stasie is.

Both mean the same thing, but al is often more conversational.

By die stasie means at the station.

The preposition by is often used for being at a place or location.

Compare:

• by die stasie = at the station
• na die stasie = to the station
• in die stasie = in the station

So in this sentence, the mother is already located there, which is why by is the natural choice.

Yes. Afrikaans uses die as the definite article for basically all nouns.

Unlike some other languages, Afrikaans does not change the for gender.

So:

• die man = the man
• die vrou = the woman
• die stasie = the station
• die stasies = the stations

This makes articles much simpler than in many European languages.

Yes, often you can, especially in everyday speech.

For example:

• Ek is seker dat my ma reeds by die stasie is.
• Ek is seker my ma is reeds by die stasie.

Both are natural.

But notice something important: if you remove dat, the second clause usually goes back to normal main-clause word order:

• with dat: my ma reeds by die stasie is
• without dat: my ma is reeds by die stasie

So dat affects both meaning and word order.

Not always. Seker can mean sure/certain, but in some contexts it can also mean probably.

In this sentence, Ek is seker dat ... clearly means I am sure that ...

But in another sentence, Hy is seker by die huis, it could mean He is probably at home, depending on context.

So seker is a word worth paying attention to, because its meaning can shift slightly.

Yes. Ma is a very common and natural word for mom/mother.

So:

• my ma = my mom / my mother

It is warm and everyday language. A more formal word is moeder, but that is less common in ordinary speech.

So in normal conversation, my ma is exactly what you would expect.

The sentence breaks down like this:

• Ek = I
• is = am
• seker = sure/certain
• dat = that
• my ma = my mother
• reeds = already
• by die stasie = at the station
• is = is

So the overall pattern is:

• main clause: Ek is seker
• subordinate clause: dat my ma reeds by die stasie is

This is a very useful sentence pattern in Afrikaans:

• Ek weet dat ... = I know that ...
• Ek dink dat ... = I think that ...
• Ek hoop dat ... = I hope that ...
• Ek is seker dat ... = I am sure that ...