Intentaron robar el dinero.

Intentaron is the preterite form of intentar (to try / to attempt).

In this sentence, it is:

• third person plural
• preterite tense
• meaning they tried or they attempted

So intentaron tells you that the trying happened as a completed past action.

After intentar, the next verb normally stays in the infinitive.

So:

• intentaron = they tried
• robar = to steal

This is the same pattern as in English:

• They tried to steal

Not:

• They tried stole

So in Spanish, intentar + infinitive is the standard structure.

Spanish often omits subject pronouns when the verb ending already makes the subject clear.

Here, intentaron already tells us the subject is they or you plural (formal), so ellos or ellas is not necessary.

You could say:

• Ellos intentaron robar el dinero

But in normal Spanish, especially when the subject is obvious, people usually just say:

• Intentaron robar el dinero

Yes, grammatically it could.

Intentaron can mean:

• they tried
• you all tried (formal plural, ustedes)

In Spain, informal plural is usually vosotros, so if you were speaking informally to several people, you would normally expect:

• intentasteis

Because of that, without more context, intentaron is most likely understood as they tried.

Spanish often uses the definite article more than English does.

Here, el dinero usually means:

• the money
• a specific amount of money already known in the context

If you said just dinero, it would sound less specific and less natural in this sentence.

So:

• robar el dinero = to steal the money

Because dinero is a thing, not a person.

The so-called personal a is usually used before a specific person (or sometimes a pet/personified being) when it is a direct object.

Compare:

• Vieron a Juan = They saw Juan
• Robaron el dinero = They stole the money

Since el dinero is not a person, there is no personal a.

Both can relate to stealing, but they are not exactly the same.

• robar = to steal / to rob
• atracar = to mug / to hold up / to rob with force, often in contexts like banks, shops, or people at knifepoint/gunpoint

So:

• robar el dinero = to steal the money
• atracar un banco = to rob a bank

In your sentence, robar is the general and natural choice.

The preterite (intentaron) presents the attempt as a completed past event.

It tells us that at some point in the past, they made an attempt to steal the money.

If you used the imperfect:

• Intentaban robar el dinero

that would sound more like:

• they were trying to steal the money
• they used to try to steal the money
• the action was ongoing, habitual, or backgrounded

So intentaron focuses on the attempt as a finished event.

A simple Spain-Spanish pronunciation guide:

• intentaron → in-ten-TA-ron
• robar → ro-BAR
• el → el
• dinero → di-NE-ro

Notes:

• In robar and dinero, the r is usually a single tapped r, not a long rolled rr
• The stress falls on:
  • ta in intentaron
  • bar in robar
  • ne in dinero

A rough English-style approximation:

• in-ten-TA-ron ro-BAR el di-NE-ro

Yes. That is a natural alternative.

• intentaron robar el dinero
• trataron de robar el dinero

Both mean they tried to steal the money.

A small difference:

• intentar + infinitive is very direct and common
• tratar de + infinitive is also common and often feels slightly more conversational in some contexts

Both are correct.

No. It only tells you that they tried.

Intentaron robar el dinero means there was an attempt, but it does not say whether they succeeded.

If you wanted to say they succeeded, you would need something like:

• Robaron el dinero = They stole the money

So intentaron robar leaves the result unknown unless more context is given.

The normal, neutral word order is:

• Intentaron robar el dinero

That is the most natural way to say it.

Spanish word order can sometimes change for emphasis, but not every rearrangement sounds natural. For example:

• El dinero intentaron robar is possible only in a marked, emphatic context
• Intentaron el dinero robar sounds unnatural

So for a learner, the best pattern is:

• conjugated verb + infinitive + object
• intentaron + robar + el dinero