Probablement el reemborsament arribarà avui.

Putting probablement first is a very natural way to frame the whole sentence as uncertain or likely: Probably, the refund will arrive today.

Catalan is fairly flexible here. You could also say:

• El reemborsament probablement arribarà avui.
• Probablement arribarà avui el reemborsament.

But Probablement el reemborsament arribarà avui is a neutral, common order.

It is an adverb made with the suffix -ment, which often works a lot like English -ly.

So:

• probable → probablement

This is a very common pattern in Catalan:

• normal → normalment
• clar / clara → clarament
• ràpid / ràpida → ràpidament

In many cases, the adverb is built from the feminine form of the adjective plus -ment.

In Catalan, a comma after a sentence adverb like probablement is often unnecessary in a short, simple sentence.

So Probablement el reemborsament arribarà avui is perfectly normal.

You might see a comma if the writer wants an extra pause or emphasis, but in everyday writing, no comma is very common.

Because Catalan normally uses an article when talking about a specific thing, and here the speaker means a particular refund that both speaker and listener can identify.

So el reemborsament means the refund.

Without the article, reemborsament would sound more general, less complete, or more like a heading or label than a normal sentence.

Yes, it is masculine. You can tell from the article el.

Also, nouns ending in -ment are very often masculine in Catalan, for example:

• el pagament
• el moviment
• el coneixement

So el reemborsament follows a very common pattern.

Arribarà is the simple future tense, third person singular, from the verb arribar.

Its basic meaning here is will arrive.

The future forms of arribar are:

• arribaré — I will arrive
• arribaràs — you will arrive
• arribarà — he/she/it will arrive
• arribarem — we will arrive
• arribareu — you all will arrive
• arribaran — they will arrive

It is third person singular because the subject, el reemborsament, is singular.

The accent shows that the stress falls on the last syllable: ar-ri-ba-rà.

It also helps mark the future ending clearly. For learners, it is useful to remember that the third person singular future often ends in -à:

• arribarà
• vindrà
• serà
• tindrà

So the accent is not optional here.

Yes. Catalan commonly uses arribar for things like packages, messages, payments, transfers, and refunds.

So el reemborsament arribarà avui sounds natural, especially in everyday language, where the idea is that the refund will come through or will arrive today.

Depending on context, other verbs are also possible, but arribar is a very normal choice.

Yes. Avui is flexible.

You can say:

• Probablement el reemborsament arribarà avui.
• El reemborsament probablement arribarà avui.
• Avui probablement arribarà el reemborsament.

The version with avui at the end is very natural and neutral. Putting avui earlier usually gives it a bit more emphasis.

No. Catalan often leaves out subject pronouns, especially when the subject is already clear.

Here the subject is explicitly stated as el reemborsament, so there is no need for any extra pronoun.

In fact, adding a pronoun here would usually sound unnecessary.

Sometimes, yes, depending on context. Catalan can use the present for near-future or scheduled events, just like English sometimes does.

For example:

• Probablement el reemborsament arriba avui.

That can work in some contexts, especially in speech. But arribarà is the clearest and most straightforward form for a prediction: the refund will arrive today.

So in this sentence, the future tense is a very natural choice.