Ŝi petas, ke mi helpu ŝin levi la skatolon, ĉar ĝi estas tro peza por unu homo.

Because after peti when someone is asking for another person’s action, Esperanto very often uses ke + a verb in the -u form.

So:

• ke introduces the clause
• helpu is the requested or desired action

The -u ending is the Esperanto form used for commands, wishes, requests, and similar ideas. Here it does not mean a simple present tense like helpas. It means something like that I help.

Yes. That is also a normal Esperanto sentence.

Both patterns are common:

• Ŝi petas, ke mi helpu...
• Ŝi petas min helpi...

They are very close in meaning. The version with ke mi helpu spells out the whole requested action as a clause. The version with min helpi uses min as the object of petas and then an infinitive.

Because ŝin is in the accusative, and here it is the direct object of helpu.

Esperanto uses -n for the direct object:

• ŝi = she
• ŝin = her

So helpu ŝin means help her.

No. In this sentence, ŝin belongs with helpu, not with levi.

The structure is:

• helpi iun fari ion = help someone do something

So here:

• ŝin = the person being helped
• levi la skatolon = the action she is being helped to do

In other words, the box is what gets lifted, not the woman.

Because it depends on helpu.

The sentence means help her lift the box, and in Esperanto that second action is usually expressed with the infinitive:

• helpi iun fari ion
• help someone do something

So levi is simply to lift.

Because levi is transitive: it means to lift/raise something.

• levi la skatolon = lift the box

But leviĝi is intransitive: it means to rise, get up, lift oneself.

For example:

• Ŝi leviĝas. = She gets up / rises.

So if the sentence were about helping her get up, you might see helpi ŝin leviĝi. But here they are lifting a box, so levi is correct.

Because la skatolon is the direct object of levi.

The thing being lifted is the box, so Esperanto marks it with the accusative:

• la skatolo = the box
• la skatolon = the box as a direct object

Because ĝi is the normal third-person singular pronoun for a thing.

Esperanto nouns do not have grammatical gender the way some languages do. A box is just a thing, so:

• ĝi = it

Here ĝi refers back to la skatolo.

Because peza is a predicate adjective after estas, not a direct object.

In Esperanto, after esti (to be), the adjective does not take -n just because some earlier noun had -n.

So:

• ĝi estas peza = it is heavy

The subject is ĝi, and peza describes that subject.

This is the normal Esperanto pattern for too ... for ...:

• tro peza = too heavy
• por unu homo = for one person

So tro peza por unu homo means too heavy for one person.

Here por shows the limit or suitability: the box is too heavy for a single person to manage alone.

No. Homo means human being or person, not specifically a male person.

So:

• homo = person / human
• viro = man
• virino = woman

Therefore unu homo means one person.

Because Esperanto normally separates subordinate clauses with commas.

So the commas help show the structure:

• Ŝi petas, ke mi helpu...
• ..., ĉar ĝi estas...

This is standard written Esperanto and makes the sentence easier to read.

It can mean either, depending on context.

Esperanto has a simple present tense in -as, and it often covers both English asks and is asking.

So Ŝi petas could mean:

• She asks
• She is asking

The surrounding context tells you which is more natural in English.