Ettersendingen begynner på flyttedatoen.

Ettersending usually means mail forwarding or mail redirection—for example, when post is sent to your new address after you move.

With the ending -en, ettersendingen means the mail forwarding or the forwarding service. In this sentence, it refers to a specific forwarding arrangement, not just the idea of forwarding in general.

The ending -en is the normal definite singular ending for many Norwegian nouns of common gender.

So:

• en ettersending = a forwarding / a mail forwarding
• ettersendingen = the forwarding / the mail forwarding

Norwegian often adds the definite article to the end of the noun instead of using a separate word like the.

Begynner is the present tense of begynne, which means to begin or to start.

So:

• å begynne = to begin
• begynner = begin / begins / is beginning, depending on context

In Norwegian, the present tense is often also used for future events when the timing is clear, so begynner can naturally mean starts here.

Norwegian is a V2 language, which means the finite verb normally comes in second position in main clauses.

In this sentence:

• Ettersendingen = first element
• begynner = second element
• på flyttedatoen = the rest

That word order is completely standard for a normal statement.

Norwegian often uses på for something happening on a particular day or at a specific point/day in the schedule.

So på flyttedatoen means on the moving date or on the move date.

Using i here would sound wrong, because i usually means in and is used more for months, years, enclosed spaces, and similar contexts.

Flyttedatoen means the moving date.

It is a compound noun:

• flytte = move
• dato = date

In Norwegian, compound nouns are usually written as one word, much more often than in English. So where English has moving date, Norwegian uses flyttedato.

With the definite ending:

• en flyttedato = a moving date
• flyttedatoen = the moving date

For the same reason as ettersendingen: it is a definite singular noun.

So:

• en flyttedato = a moving date
• flyttedatoen = the moving date

This tells you the sentence is talking about a specific, known move date.

Both nouns are definite because the sentence refers to specific things:

• ettersendingen = the particular mail forwarding arrangement
• flyttedatoen = the particular move date

This is very natural in Norwegian when both the speaker and listener know which forwarding service and which date are being discussed.

Yes. Starter would also sound natural in many contexts.

For example:

• Ettersendingen begynner på flyttedatoen
• Ettersendingen starter på flyttedatoen

Both can work. Begynner is a very general begins/starts, while starter can sometimes sound slightly more like starts up, but in everyday usage the difference is often small.

Yes, a big one.

• begynner = begins / starts
• begynnes = is begun / is started (passive)

In your sentence, begynner is correct because ettersendingen is the thing that starts. Using begynnes would change the structure and sound much less natural here.

More or less, yes:

• Ettersendingen = the forwarding
• begynner = begins
• på = on
• flyttedatoen = the moving date

A literal translation is understandable, but in natural English you would often say something like Mail forwarding starts on the moving date or Forwarding begins on your move date.

A rough guide for an English speaker is:

• ettersendingen ≈ ET-ter-sen-ding-en
• flyttedatoen ≈ FLYT-te-da-too-en

A few helpful notes:

• y in flytte is not like English y; it is a rounded vowel that many English speakers find tricky.
• Double consonants such as tt usually show that the vowel before them is short.
• The ending -en is usually pronounced lightly.

If you want, I can also break these words down into a more detailed pronunciation guide.

Not always. The sentence is correct and natural, especially in formal or service-related contexts, such as the post office, a website, or a confirmation message.

In everyday speech, someone might also say things like:

• Ettersendingen starter når du flytter.
• Posten blir ettersendt fra flyttedatoen.

So your sentence is good Norwegian, but there are several natural ways to express the same idea.