Te guardo un sitio en la biblioteca.

Te is the indirect object pronoun for you in the singular familiar form (tú).

So Te guardo un sitio literally means something like I save you a place, which in natural English is I’ll save you a spot/seat.

Spanish often uses an indirect object pronoun where English would use for you:

• Te preparo un café = I’ll make you a coffee
• Te guardo un sitio = I’ll save you a place

Spanish very often uses the present tense to talk about a near future action, especially when it sounds like an immediate decision, offer, or promise.

So:

• Te guardo un sitio = I’ll save you a spot
• Te guardaré un sitio = also correct, but a bit more explicitly future

In everyday conversation, te guardo sounds very natural and common.

The basic meaning of guardar is to keep, to store, or to put away, but in this context it means to save or to hold a place for someone.

So guardar un sitio means:

• to save someone a spot
• to keep a place free for someone

This is a very common use in Spain:

• Guárdame sitio = Save me a spot
• Te guardo mesa = I’ll save you a table

Because sitio is flexible. It can mean place, space, spot, or even seat, depending on context.

In la biblioteca, un sitio usually means:

• a place to sit
• a free spot at a table
• a study space

So although the literal translation is a place, the natural meaning is often a spot or a seat.

Yes, but it changes the nuance a little.

• un sitio = a spot/place, more general and very natural here
• un asiento = a seat, more specifically the physical seat itself

In a library, sitio is often more idiomatic because you are usually saving not just the chair, but the whole study space. So Te guardo un sitio en la biblioteca sounds very natural.

You can say Guardo un sitio para ti, and it is correct. But Spanish very often prefers the indirect object pronoun when the person benefiting from the action is clear.

So:

• Te guardo un sitio = very natural
• Guardo un sitio para ti = also correct
• Te guardo un sitio para ti = possible, but usually more emphatic than necessary

Using te is the most normal everyday option.

Because object pronouns like me, te, lo, la, le, nos normally go before a conjugated verb.

So:

• Te guardo un sitio = correct
• Guardo te un sitio = incorrect

With an infinitive, the pronoun can attach to the end:

• Voy a guardarte un sitio

With a conjugated verb on its own, it goes before:

• Te guardo un sitio

Yes. Te is for one person addressed as tú.

If you are speaking to more than one person in Spain, you would normally use os:

• Os guardo un sitio = I’ll save you all a spot

If you are speaking politely to one person, you would use le:

• Le guardo un sitio = I’ll save you a spot (formal)

Because en expresses location: in / at the library.

• en la biblioteca = in/at the library
• a la biblioteca = to the library

So:

• Te guardo un sitio en la biblioteca = I’m saving you a spot in the library
• Voy a la biblioteca = I’m going to the library

Yes. In practice, it can cover both ideas depending on context.

• I’m saving you a place if the action is already happening now
• I’ll save you a place if it is an offer or immediate future action

In many real situations, English would prefer I’ll save you a spot, while Spanish naturally uses the present: Te guardo un sitio.

It works in many varieties of Spanish, but sitio for spot/place is especially common and natural in Spain.

In other regions, people may also say things like:

• Te aparto un lugar
• Te guardo un lugar
• Te reservo un sitio

But in Spain, Te guardo un sitio sounds very normal in everyday speech.

Sometimes, but reservar and guardar are not exactly the same.

• reservar = to reserve/book
• guardar = to save/hold/keep

In a library, if you are physically keeping a free spot for someone who is about to arrive, guardar is the natural choice.

Te reservo un sitio sounds more like formally reserving a place, which is less likely in this context.

Yes. The natural informal request would be:

• Guárdame un sitio

This is formed with:

• guarda = imperative of guardar
• me = for me / me

Literally, it is Save me a place, and naturally it means Save me a spot.

In Spain, that is a very common thing to say.