Jeg vil læse det hele i aften.

It can suggest both, depending on context.

In Danish, vil often expresses:

• future intention: I will / I’m going to
• desire or willingness: I want to / I’m willing to

So Jeg vil læse det hele i aften can mean something like:

• I’ll read it all tonight
• I’m going to read it all tonight
• sometimes even I want to read it all tonight

Very often, it sounds like a plan or intention rather than a simple neutral future. Danish also often uses the present tense for future meaning, so Jeg læser det hele i aften can also be natural.

Because vil is a modal verb, and modal verbs in Danish are followed by a bare infinitive.

So:

• vil læse = will read / want to read
• not vil læser

This is similar to English:

• I will read
• not I will reads

Common Danish modal verbs include kan, skal, vil, må, bør.

After a modal verb like vil, Danish normally does not use at.

So you say:

• Jeg vil læse
• not Jeg vil at læse

Compare:

• Jeg prøver at læse = I’m trying to read
• Jeg vil læse = I want to / will read

So the rule is: after modal verbs, use the infinitive directly.

Because Danish main clauses follow the V2 rule: the finite verb usually comes in the second position.

In this sentence:

• Jeg = subject
• vil = finite verb
• læse = infinitive
• det hele = object
• i aften = time expression

So the normal order is: Subject + finite verb + infinitive + object + time

If you move something else to the front, the finite verb still stays second:

• I aften vil jeg læse det hele.

That is very typical Danish word order.

Det hele means the whole thing, all of it, or it all.

It is a very common Danish expression. In this sentence, it refers to everything that is going to be read.

Examples:

• Jeg forstod det hele. = I understood all of it.
• Hun spiste det hele. = She ate all of it.

So in your sentence, læse det hele means read the whole thing / read all of it.

Because det hele is a fixed, very common Danish expression.

With a noun, hele usually comes before the noun:

• hele bogen = the whole book
• hele dagen = the whole day

But when Danish uses this pronoun-style expression meaning the whole thing / all of it, the normal form is:

• det hele

So:

• Jeg vil læse hele bogen i aften. = I want to read the whole book tonight.
• Jeg vil læse det hele i aften. = I want to read all of it / the whole thing tonight.

In det hele, det is part of the fixed expression det hele, which means the whole thing / all of it.

It does not always behave like a simple gender-matching pronoun. Instead, it often refers to something as a whole, almost like the whole matter or the whole thing.

So even if the thing you are talking about might be a noun with en, Danish very often still uses det hele when the meaning is all of it in a general sense.

If you want to be more specific with a noun, Danish often prefers:

• hele bogen = the whole book
• hele artiklen = the whole article

I aften means tonight or this evening.

It refers to a specific evening: the one coming up now, or the current evening.

For example:

• Vi ses i aften. = See you tonight.
• Jeg arbejder i aften. = I’m working tonight.

This is different from om aftenen, which usually means in the evening in a general or habitual sense:

• Jeg læser om aftenen. = I read in the evenings / in the evening.

So:

• i aften = tonight, this evening
• om aftenen = in the evening(s), generally

Yes, absolutely.

That sentence is also correct:

• I aften vil jeg læse det hele.

The meaning is basically the same, but the emphasis changes slightly. Putting I aften first highlights the time:

• Tonight, I’m going to read all of it.

Because of Danish V2 word order, once I aften moves to the front, the finite verb vil still has to stay in second position:

• I aften vil jeg ...
• not I aften jeg vil ...

You would usually put ikke after the finite verb and before the infinitive:

• Jeg vil ikke læse det hele i aften.

That is the normal placement in a main clause with a modal verb:

• subject + finite verb + ikke
  • infinitive

So:

• Jeg vil læse det hele i aften. = I will read it all tonight.
• Jeg vil ikke læse det hele i aften. = I will not read it all tonight.

A rough English-friendly approximation is LEH-suh.

A few details:

• æ is a front vowel somewhat like the vowel in cat, but not exactly the same.
• the final e is weak, like uh / schwa
• the s is a normal s sound here

So læse sounds roughly like LEH-suh.

If you want to sound natural, it is better to keep the second syllable very light:

• LÆ-se

And jeg vil læse is usually said quite smoothly in normal speech.