Signora, Le tengo da parte una fetta di torta.

Here Le is the formal you in an object form, used to address someone politely.

The capital letter is a traditional way to show respect and to distinguish it from le, which can also mean them or the (feminine plural object pronoun/article, depending on context). In modern Italian, especially informal writing, many people just write le in lowercase, but the capital L is still common in polite or customer-service language.

So Le here is polite, not required by grammar, but very normal in formal contexts.

Le is an indirect object pronoun, meaning to you or for you in a formal, polite way.

So:

• Le tengo da parte... = I’m keeping aside... for you
• informal version: Ti tengo da parte...
• very formal or polite version: Le tengo da parte...

A useful point: this Le is not the subject. The subject is an understood I, which is why the verb is tengo and not a third-person form.

Because Le here is not the subject. It means to/for you, not you as the person doing the action.

The hidden subject is io = I:

• (Io) tengo = I keep / I set aside
• Le = for you (formal)

So the structure is basically:

• (Io) Le tengo da parte una fetta di torta.
• I am setting aside a slice of cake for you.

If Lei were the subject, then the verb would indeed be third person, but that is not what is happening here.

Yes. Tenere has several meanings, including to hold, to keep, and in some expressions to reserve or to keep aside.

In this sentence, the key expression is tenere da parte, which means:

• to keep aside
• to set aside
• to reserve
• to save for someone

So this is not the literal physical idea of holding something in your hand. It is the idiomatic shop/customer-service meaning: keeping something available for a customer.

Da parte literally suggests something like to the side, but in this expression it means aside.

So tenere da parte is an idiom:

• tenere da parte qualcosa = to keep something aside / reserved

You will also see mettere da parte, which can mean:

• to put aside
• to save
• sometimes even to save money

In this sentence, da parte helps create the idea of reserving the slice rather than just possessing it.

Una is used because the speaker is referring to a slice of cake, not to one already specifically identified.

So:

• una fetta di torta = a slice of cake
• la fetta di torta = the slice of cake

If both speaker and listener already knew exactly which slice was meant, la could be possible. But in a normal shop interaction, una fetta di torta is the natural choice because it introduces the item as one slice, not a previously defined one.

Because Italian often uses di to link a quantity, piece, or portion to the thing it comes from.

So:

• una fetta di torta = a slice of cake
• un bicchiere d’acqua = a glass of water
• un pezzo di pane = a piece of bread

This is very similar to English of in expressions like a slice of cake.

Fetta is more specific. It means a slice, especially something cut in a flat slice, like cake, bread, ham, or pizza in some contexts.

• fetta di torta = slice of cake
• pezzo di torta = piece of cake

Both can be understood, but fetta is more precise and natural if you mean an actual slice. Pezzo is broader and less specific.

Because Signora here is a direct form of address: the speaker is talking to the woman directly, like Ma’am or Madam.

When you address someone directly in Italian, you normally do not use an article:

• Signora, aspetti un attimo.
• Dottore, può venire?
• Marco, ascolta.

The comma helps show that Signora is being used as a vocative, not as the subject of the sentence.

Yes, but the tone changes.

• Ti tengo da parte... = informal for you
• Le tengo da parte... = formal/polite for you

So the choice depends on the relationship:

• Ti for friends, family, children, people you address informally
• Le for customers, strangers, older people in polite situations, or formal service contexts

Because the sentence begins with Signora, the formal Le fits very naturally.

Yes, very much so. It sounds like customer-service Italian.

A shop assistant might say this when they mean:

• they will reserve a slice for the customer
• they will not sell it to someone else
• they are keeping it available for her

In everyday spoken Italian, a very common alternative is:

• Le metto da parte una fetta di torta.

That often sounds slightly more immediate: I’ll set aside a slice of cake for you.

Le tengo da parte... is also perfectly natural and gives the idea that the slice is being kept reserved.

Because Italian normally leaves out subject pronouns when the verb already makes the subject clear.

Here tengo clearly shows I:

• tengo = I keep / I set aside

So io is unnecessary unless you want emphasis:

• Io Le tengo da parte una fetta di torta.

That version might sound more emphatic, like I’ll be the one to keep a slice aside for you or I will keep one aside for you. In normal speech, the version without io is more natural.