Devo preparare la cena prima di uscire.

Because Italian often drops the subject pronoun when it is clear from the verb ending.

• Devo already means I must / I have to
• The ending -o tells you the subject is I

So Devo preparare la cena is perfectly natural Italian.
You could say Io devo if you want extra emphasis, such as:

• Io devo preparare la cena, non tu = I have to make dinner, not you

Devo is the first-person singular form of dovere, which means to have to, must, or to be supposed to.

In this sentence:

• devo preparare = I have to prepare
• devo uscire would mean I have to go out

So the pattern is:

• dovere + infinitive

Examples:

• Devo studiare = I have to study
• Devi lavorare = You have to work
• Dobbiamo partire = We have to leave

Because after a modal verb like dovere, Italian normally uses the infinitive of the next verb.

So:

• Devo preparare = I have to prepare
• Posso uscire = I can go out
• Voglio mangiare = I want to eat

You do not conjugate the second verb here.
That is why it is devo preparare, not devo preparo.

In Italian, the definite article is often used where English would not use the.

So:

• preparare la cena = prepare dinner / make dinner

Even though English often says just dinner, Italian commonly says la cena.

This is very natural with meals and other everyday nouns:

• la colazione = breakfast
• il pranzo = lunch
• la cena = dinner

So preparare la cena is the standard, natural phrasing.

It means before going out or before leaving, and the structure is:

• prima di + infinitive

So:

• prima di uscire = before going out
• prima di mangiare = before eating
• prima di partire = before leaving

This structure is used when the subject of both actions is the same.

In your sentence, the same person:

• has to prepare dinner
• and then go out

So prima di uscire is exactly the right structure.

Because after di in the pattern prima di + verb, Italian uses the infinitive, not a conjugated form.

So you say:

• prima di uscire

Not:

• prima di esco

Compare:

• Devo mangiare prima di uscire = I have to eat before going out
• Prima di partire, chiamo mia madre = Before leaving, I call my mother

It can mean both, depending on context.

In this sentence, uscire most naturally means:

• to go out
• or more generally to leave

So prima di uscire could be understood as:

• before going out
• before leaving the house
• before heading out

The exact English wording depends on context, but the Italian is very natural either way.

Yes. Italian word order is flexible, especially with time expressions like prima di uscire.

You can say:

• Devo preparare la cena prima di uscire.
• Prima di uscire, devo preparare la cena.

Both are correct. The second version puts more focus on the before going out part.

Both can be used, but they are not exactly the same.

• preparare la cena = to prepare dinner
• cucinare la cena = to cook dinner

Preparare is a bit broader. It can include:

• cooking
• setting things up
• getting the meal ready in general

Cucinare focuses more specifically on the act of cooking.

So in this sentence, preparare la cena sounds very natural and slightly more general.

It can cover both ideas. Dovere often translates as either must or have to, depending on context.

So Devo preparare la cena could mean:

• I must prepare dinner
• I have to prepare dinner

In everyday speech, English often prefers have to, while Italian uses dovere very naturally for both.

The exact strength depends on the situation:

• a personal obligation
• a practical necessity
• a plan that needs to happen

Not in this sentence.

When the subject is the same, Italian normally uses:

• prima di + infinitive

So:

• Devo preparare la cena prima di uscire.

If you use prima che, you usually need a new clause with a conjugated verb, and very often the subjunctive:

• Devo preparare la cena prima che lui esca. = I have to prepare dinner before he goes out.

So:

• prima di uscire = before going out
• prima che lui esca = before he goes out

That is an important difference.