Mercatrix pollicetur se cras pira recentiora allaturam esse, si imber desierit.

Because pollicetur is a deponent verb.

Deponent verbs:

• have passive-looking forms
• but active meanings

So:

• pollicetur = she promises
• not she is promised

Its dictionary form is polliceor, polliceri, pollicitus sum.

Because after verbs like pollicetur (promises), Latin often uses an indirect statement.

The standard pattern is:

• accusative subject
  • infinitive

So here:

• se = the subject of the reported statement, in the accusative
• allaturam esse = will bring

Together, se ... allaturam esse means that she will bring.

This is very common in Latin after verbs of:

• saying
• thinking
• knowing
• promising
• perceiving

Because se is the reflexive pronoun. It refers back to the subject of the main verb, which is Mercatrix.

So:

• Mercatrix pollicetur se ... allaturam esse
• The merchant promises that she herself will bring ...

If Latin used eam, that would normally point to some other woman, not back to Mercatrix.

So se is used because the one promising and the one who will bring the pears are the same person.

Because allaturam esse is a future active infinitive, and its participle agrees with the subject of the infinitive.

The subject of the infinitive is se, which refers to Mercatrix, a woman.

So the participle must be:

• feminine
• singular
• accusative

Hence:

• allaturam esse = to be going to bring / to bring in the future

If the subject were masculine, Latin would use allaturum esse.

It comes from affero / adfero, meaning bring.

This verb is irregular. Its principal parts are commonly given as:

• affero (or adfero) = I bring
• afferre = to bring
• attuli = I brought
• allatus = brought

The future infinitive is formed with the future participle plus esse:

• allaturam esse = to be about to bring, often best translated simply as will bring

Pira is accusative plural neuter.

It is the direct object of allaturam esse:

• she will bring pears

The noun is pirum in the singular, meaning a pear.

So:

• pirum = pear
• pira = pears

Here it is accusative because it is the thing being brought.

Recentiora is the comparative form of recens (fresh).

Here it agrees with pira, so it is:

• neuter
• plural
• accusative

Thus:

• pira recentiora = fresher pears

The ending -iora is what you expect for a comparative adjective agreeing with a neuter plural noun.

Because the idea is not just fresh pears, but fresher pears.

The comparison may be:

• explicit in the wider context, or
• just implied

For example, it may suggest:

• fresher than the pears available now
• fresher than earlier ones
• fresher than someone else's

Latin, like English, can use a comparative without spelling out the second half.

So recentiora does not need a written quam ... phrase in the sentence.

Here desierit is most naturally understood as future perfect indicative:

• si imber desierit = if the rain has stopped / if the rain stops

This is a very common Latin pattern in future conditions:

• future perfect in the if-clause
• some kind of future sense in the main clause

That fits this sentence well, because the promise is about a future action.

Formally, desierit can look like either:

• future perfect indicative, or
• perfect subjunctive

But after si, in a sentence like this, the future perfect indicative sense is the normal one.

It is part of the content of the promise.

The merchant promises:

• se cras pira recentiora allaturam esse, si imber desierit

In other words, what she promises is conditional:

• she will bring the pears
• if the rain stops

So the whole idea being promised is:

• that she will bring fresher pears tomorrow if the rain stops

Yes. Cras means tomorrow, and Latin word order is fairly flexible.

Here it stands before pira recentiora allaturam esse, so it naturally goes with the future action:

• she promises that she will bring pears tomorrow

Latin often arranges words for emphasis or flow rather than for strict word-order rules.

So other placements would also be possible, for example:

• Mercatrix se pira recentiora cras allaturam esse pollicetur
• Mercatrix pollicetur se pira cras recentiora allaturam esse

But the given order is perfectly natural.

The indirect statement is:

• se cras pira recentiora allaturam esse

A direct version would use a normal first-person future idea, something like:

• Cras pira recentiora allatura sum, si imber desierit.

That means:

• Tomorrow I will bring fresher pears, if the rain stops.

Then in reported form, Latin changes that into:

• se ... allaturam esse

So this sentence is a good example of how Latin turns a direct future statement into an indirect statement.