La dependenta ens ha obert el provador perquè la meva amiga es vol provar un vestit blanc.

La dependenta means the shop assistant or the saleswoman.

• dependent / dependenta = shop assistant
• Here it is feminine: la dependenta
• The masculine form is el dependent

In this sentence, it refers to a female employee in a shop.

Ens means us.

In this sentence, ens ha obert el provador means has opened the fitting room for us.

A few useful points:

• ens is the 1st person plural object pronoun: us / to us / for us
• In Catalan, object pronouns usually go before the conjugated verb:
  • ens ha obert
  • literally: to-us has opened

So the structure is very normal Catalan word order for pronouns.

Ha obert is the present perfect in Catalan.

It is formed with:

• haver in the present tense + past participle

So:

• ha = has
• obert = opened

Together:

• ha obert = has opened

This tense is very common in spoken Catalan, especially for a completed action connected to the present situation. Here, the fitting room has just been opened, and that matters now.

Compare:

• obre = opens / is opening
• va obrir = opened
• ha obert = has opened

El provador means the fitting room or the changing room in a shop.

It comes from the idea of trying clothes on.

Related words:

• provar = to try
• emprovador = fitting room (also used in Catalan, depending on region and context)
• provador = fitting room / changing room

So obrir el provador means to open or unlock the fitting room for someone.

Because perquè means because.

This is a very common learner question because Catalan distinguishes:

• perquè = because
• per què = why / for what
• per a què = what for

So in this sentence:

• ... perquè la meva amiga...
• ... because my friend...

The accent helps distinguish the conjunction perquè from the question form per què.

In Catalan, possessives are usually used with the definite article.

So Catalan normally says:

• la meva amiga = my friend
• el meu germà = my brother
• la nostra casa = our house

This is different from English, where you just say my friend without the.

So:

• la meva amiga is the normal Catalan form

There are some exceptions, especially with certain family terms in some contexts, but for most learners the safe rule is:

article + possessive + noun

Es vol provar means wants to try on.

More literally:

• vol = wants
• provar = to try
• es = herself / on herself

The key point is that provar-se means to try on clothes.

So:

• provar un vestit can mean to try a dress in a general sense
• provar-se un vestit clearly means to try a dress on

In this sentence:

• la meva amiga es vol provar un vestit blanc
• my friend wants to try on a white dress

The pronoun es shows that the action is being done on herself.

Because in Catalan, with a conjugated verb plus an infinitive, object/reflexive pronouns can often go before the conjugated verb.

So these two patterns are possible:

• es vol provar un vestit
• vol provar-se un vestit

Both mean essentially the same thing: she wants to try on a dress.

In your sentence, Catalan uses clitic climbing, where the pronoun moves before the conjugated verb:

• es vol provar

This is very common and natural.

Vol is the 3rd person singular form of voler (to want).

Conjugation of voler in the present:

• vull = I want
• vols = you want
• vol = he/she/it wants
• volem = we want
• voleu = you all want
• volen = they want

Since the subject is la meva amiga (my friend), Catalan uses:

• vol = she wants

Because in Catalan, adjectives usually come after the noun, especially descriptive adjectives like colors.

So:

• un vestit blanc = a white dress

This is the normal order:

• noun + adjective

Examples:

• una camisa blava = a blue shirt
• un cotxe vermell = a red car
• una casa gran = a big house

With color adjectives, post-noun position is especially standard:

• vestit blanc

Yes, vestit can mean dress, but it can also have other related meanings depending on context.

Common possibilities include:

• dress
• suit
• garment / outfit

Here, because the sentence says la meva amiga and she is trying on un vestit blanc, the most natural English translation is a white dress.

So the exact English word depends on context, but dress is clearly the intended meaning here.

Because Catalan often expresses that idea with an object pronoun like ens.

So:

• ens ha obert el provador literally looks like
• has opened the fitting room to/for us

English often needs an extra preposition:

• opened the fitting room for us

Catalan can express that meaning more compactly through the clitic pronoun ens.

The sentence breaks down like this:

• La dependenta = the shop assistant
• ens ha obert el provador = has opened the fitting room for us
• perquè = because
• la meva amiga = my friend
• es vol provar un vestit blanc = wants to try on a white dress

So the structure is:

[Main clause] + perquè + [reason clause]

More literally:

The shop assistant has opened the fitting room for us because my friend wants to try on a white dress.

Yes, it is natural and idiomatic.

It uses several very normal Catalan features:

• article + possessive: la meva amiga
• present perfect: ha obert
• object pronoun before the verb: ens ha obert
• reflexive/pronominal form for trying on clothes: es vol provar
• adjective after the noun: vestit blanc

So it is a good example of everyday Catalan, especially in a shopping context.