Nostra interest ut vectura sine mora incipiat.

Here interest is not the ordinary English-like verb to interest someone.

It is the Latin impersonal expression interest, literally it concerns or it matters. In smoother English, this sentence means something like:

• it is in our interest that ...
• it matters to us that ...
• we care that ...

So Nostra interest does not mean our thing interests. It is a fixed Latin idiom.

With interest and refert, Latin often uses a special idiomatic form to show whose interest it is.

For the 1st and 2nd persons, Latin commonly uses the possessive adjectives:

• mea interest = it concerns me / it matters to me
• tua interest = it concerns you
• nostra interest = it concerns us
• vestra interest = it concerns you all

So nostra here is the normal idiom.

A learner may expect nostri interest, because interest often takes a genitive with nouns, but with these pronoun-based forms Latin usually prefers mea, tua, nostra, vestra, and so on.

In other words, nostra interest is something you should largely learn as a set phrase.

Formally, nostra is the ablative feminine singular form of noster, nostra, nostrum.

However, in this construction, it is best not to over-translate it as a normal ablative with a visible noun. It is part of the fixed idiom used with interest.

So the most useful thing for a learner is:

• recognize nostra interest as a standard expression
• translate it as it is in our interest or it matters to us

The ut clause tells you what matters.

So:

• Nostra interest = it matters to us
• ut vectura sine mora incipiat = that the transport/shipment begin without delay

Put together:

• It matters to us that the shipment begins without delay
• or more naturally, It is in our interest that the shipment begin without delay

After expressions like interest, Latin commonly uses ut + subjunctive to introduce this kind of content clause.

Because it is inside the ut clause after interest.

Latin normally uses the subjunctive in this kind of subordinate clause. So incipiat is not saying that the action is doubtful; it is simply the grammar required by the construction.

Incipiat is:

• present
• active
• subjunctive
• 3rd person singular

from incipio, incipere = to begin

The singular makes sense because its subject, vectura, is singular.

Vectura is the subject of incipiat.

So in the clause

• ut vectura sine mora incipiat

the word vectura is the thing that is to begin.

Grammatically, it is nominative singular feminine.

Depending on context, vectura can mean things like:

• transport
• shipment
• delivery
• carriage

So the exact English word depends on what kind of text this is.

Sine mora means without delay.

The preposition sine always takes the ablative, so:

• sine = without
• mora = ablative singular of mora, meaning delay

This is a very common Latin expression.

Yes, that is a helpful way to understand it.

A very literal breakdown would be:

• Nostra interest = it is of concern to us
• ut vectura sine mora incipiat = that the shipment begin without delay

In natural English, though, you would usually say:

• It is in our interest that the shipment begin without delay
• It matters to us that the transport start without delay

So the literal sense is useful for grammar, but smoother English is usually better for translation.

The word order is fairly normal, but Latin word order is flexible.

This sentence begins with Nostra interest, which immediately highlights the idea this matters to us. Then the clause introduced by ut explains what matters.

So the structure is:

• Nostra interest = main idea
• ut vectura sine mora incipiat = explanation of what matters

Latin could rearrange some of these words without changing the basic meaning, but this order is clear and natural.

It expresses importance/concern, not just a neutral fact.

The sentence does not merely say that the shipment begins without delay. It says that it matters to us that this should happen.

That is one reason the subjunctive fits well here: the clause presents the action as the thing that is important, intended, or at issue, rather than just stating it flatly as a bare fact.