Hostesaften får hende til at sove bedre, når hosten er stærk om natten.

Hostesaften is the definite singular form of hostesaft.

• hoste = cough
• saft = juice / syrup
• together hostesaft = cough syrup
• -en = the definite ending for a common-gender noun

So hostesaften means the cough syrup.

Because hende is the object form of she/her, while hun is the subject form.

Here, the cough syrup is doing something to her, so Danish uses the object pronoun:

• Hun sover. = She sleeps.
• Hostesaften får hende til at sove. = The cough syrup makes/helps her sleep.

So hende is correct because she is not the subject of får.

This is a very common Danish pattern:

få + someone + til at + infinitive

It means make/get someone to do something.

So:

• får hende til at sove = makes/gets her to sleep

In natural English, this is often translated more softly as helps her sleep, depending on context.

Also, this is a good reminder that få does not only mean get/receive. It can also mean cause or make happen in this structure.

Because bedre means better, and the sentence is comparing her sleep to how she would otherwise sleep.

With sove, Danish uses an adverb:

• sove godt = sleep well
• sove bedre = sleep better

So bedre is the comparative form here. It describes how she sleeps.

Hosten means the cough, while en hoste means a cough.

The definite form is used because the sentence is referring to a specific cough already understood from the context — most likely her cough.

So:

• en hoste = a cough, any cough
• hosten = the cough, the one being talked about

This is very natural in Danish.

Here når means when or whenever.

It is often used for things that happen regularly, generally, or whenever a certain situation occurs.

So in this sentence, the idea is:

• when/whenever the cough is severe at night

This is different from:

• hvis = if
• da = when for a specific past event

So når fits well because this is a general situation, not one single past event.

Because når introduces a subordinate clause, and Danish subordinate clauses do not use main-clause word order.

In a main clause, Danish normally puts the finite verb in second position:

• Hostesaften får hende til at sove bedre.

But after når, the clause is subordinate, so the subject comes before the verb:

• når hosten er stærk om natten

Not:

• når er hosten stærk om natten

A useful comparison:

• Hosten er stærk om natten. = main clause
• når hosten er stærk om natten = subordinate clause

Om natten means at night / during the night in a general or habitual sense.

So this sentence is talking about what happens at night in general.

By contrast:

• i nat = tonight (one specific night)

So:

• om natten = at night, generally
• i nat = tonight, specifically

Literally, yes — stærk means strong. But in this sentence, it is better understood as severe, bad, or intense.

So hosten er stærk does not mean the cough is physically strong in some odd way. It means the cough is severe.

This kind of wording is normal in Danish.

Yes. Danish can move that clause to the front:

Når hosten er stærk om natten, får hostesaften hende til at sove bedre.

That means the same thing.

Notice that when the subordinate clause comes first, the main clause still follows normal Danish V2 word order, so får comes before the subject-like material that follows. This is a common feature of Danish sentence structure.