Mercatrix Massiliam proficisci vult, quia ibi linum bonum et purpuram claram invenire sperat.

With names of cities, Latin often uses the accusative without a preposition to show motion toward a place.

So:

• Massilia = Marseilles / Massilia
• Massiliam = to Massilia

This is a very common Latin idiom:

• Romam it = he goes to Rome
• Athenas navigat = she sails to Athens

So Massiliam proficisci means to set out for Massilia.

Vult means wants, and in Latin verbs like want, can, must, begin, dare are often followed by an infinitive.

So:

• vult proficisci = wants to set out / wants to leave

This is called a complementary infinitive: the infinitive completes the meaning of the main verb.

Compare:

• vult venire = she wants to come
• potest videre = he can see

Because proficiscor, proficisci is a deponent verb.

Deponent verbs:

• have passive-looking forms
• but active meanings

So although proficisci looks passive in form, it means to set out, to depart, or to leave.

Other common deponent verbs are:

• loqui = to speak
• sequi = to follow
• hortari = to encourage

Mercatrix is nominative singular.

That tells us it is the subject of the sentence:

• mercatrix = the merchant woman / female merchant

She is the one who:

• wants (vult)
• hopes (sperat)
• to set out (proficisci)
• to find (invenire)

So the understood subject of both infinitives is the same mercatrix.

Just like vult can be followed by an infinitive, sperat can too.

• sperat invenire = she hopes to find

Again, the subject of invenire is understood from the main subject, mercatrix.

So Latin does not need to repeat she:

• mercatrix ... sperat invenire = the merchant hopes to find

Because adjectives must agree with the nouns they describe in:

• gender
• number
• case

Here:

• linum is neuter singular accusative
• so bonum is also neuter singular accusative

And:

• purpuram is feminine singular accusative
• so claram is also feminine singular accusative

So:

• linum bonum = good flax/linen
• purpuram claram = bright purple dye / fine purple

They are the direct objects of invenire.

The merchant hopes to find what?

• linum bonum
• purpuram claram

Since they receive the action of finding, they are in the accusative case.

Ibi is an adverb meaning there.

It refers to the place already mentioned, Massiliam. So the sense is:

• she wants to go to Massilia
• because there she hopes to find good linen and bright purple dye

Latin often uses ibi this way to avoid repeating the place name.

Quia means because.

It introduces the reason:

• Mercatrix Massiliam proficisci vult = The merchant wants to set out for Massilia
• quia ... sperat = because ... she hopes

So the second clause explains why she wants to go.

Latin word order is much freer than English word order because Latin uses endings to show grammatical relationships.

A more word-for-word arrangement might be:

• The merchant wants to set out for Massilia, because there she hopes to find good linen and bright purple dye.

But Latin can move words around for emphasis or style. For example:

• Massiliam comes before proficisci to highlight the destination
• linum bonum et purpuram claram comes before invenire so the things hoped for are presented first

Even when the order changes, the case endings keep the meaning clear.

Not exactly. Proficisci means something like:

• to set out
• to depart
• to start a journey
• sometimes to go forth

So it is a bit more specific than simple ire (to go). It suggests the beginning of a journey, which fits well with travel to another city.

In this sentence, it most naturally means hopes to find.

Since the subject of sperat and invenire is the same person, Latin commonly uses the infinitive:

• sperat invenire = she hopes to find

In English, both of these can express the idea:

• she hopes to find
• she hopes that she will find

But Latin here chooses the more compact infinitive construction.

Mercatrix is a third-declension feminine noun meaning female merchant or woman trader.

It is related to mercator:

• mercator = merchant (masculine)
• mercatrix = merchant woman (feminine)

A learner may notice that -trix is a common feminine ending in some agent nouns, as in:

• nutrix = nurse
• genetrix = mother / she who gives birth

So mercatrix clearly identifies the subject as female.