La libreria mi dà un segnalibro in regalo con il libro.

No. In Italian, libreria usually means bookstore or sometimes bookcase/bookshelf, not library.

The word for library is biblioteca.

So in this sentence, La libreria means the bookstore.

Mi means to me.

It is an indirect object pronoun, and in Italian these short pronouns normally go before the conjugated verb:

• mi dà = gives me / gives to me

English puts me after the verb, but Italian usually puts mi before it.

A fuller version would be dà a me, but that is normally used only for emphasis.

The accent distinguishes dà (from the verb dare, he/she/it gives) from da (from, by, at, depending on context).

So:

• dà = gives
• da = from / by / at

This accent is standard and important in writing.

Dà is the present indicative of dare.

Here it means gives or is giving, depending on context.

The verb dare is irregular, so its present forms are worth learning:

• io do
• tu dai
• lui/lei dà
• noi diamo
• voi date
• loro danno

Un is the indefinite article, so un segnalibro means a bookmark.

It is used because the bookmark is being introduced as something not previously identified.

If you said il segnalibro, that would usually mean the bookmark, as if both speaker and listener already knew which bookmark was being talked about.

In regalo is a common expression meaning as a gift or for free as a bonus.

So dà un segnalibro in regalo means the bookstore gives the bookmark as a free extra, not as something you pay for separately.

A similar expression you may also see is in omaggio.

It most naturally means with the book: the bookmark is given together with the book.

So the idea is that when you get or buy the book, the bookstore gives you a bookmark as a gift along with it.

In other words, con il libro modifies the whole giving situation, not just regalo by itself.

Il libro suggests a specific book in the situation, even if it has not been named explicitly.

For example, it can mean the book I’m buying / the book in question.

If you said con un libro, it would sound more general: with a book.

So con il libro often feels more natural when talking about a particular purchase or item already understood from context.

Yes. A very natural alternative is:

• La libreria mi regala un segnalibro con il libro.

This uses regalare = to give as a gift.

Another possibility is:

• La libreria mi dà un segnalibro in omaggio con il libro.

All of these are natural, though in regalo and in omaggio sound especially common in promotional or store-related language.

Italian and English organize pronouns differently.

English:

• The bookstore gives me a bookmark

Italian:

• La libreria mi dà un segnalibro

The main difference is that the short pronoun mi comes before the verb in Italian.

The rest of the sentence is actually fairly straightforward:

• La libreria = subject
• mi = indirect object
• dà = verb
• un segnalibro = direct object
• in regalo = expression meaning as a gift
• con il libro = with the book

Yes. La libreria is the subject of the sentence, and dà agrees with it in the third-person singular.

So the structure is:

• La libreria = the bookstore
• dà = gives

That is why the verb is dà and not a plural form like danno.

Yes. Depending on context, libreria can also mean bookcase or bookshelf.

For example:

• Ho messo il romanzo nella libreria = I put the novel in the bookcase

But in your sentence, a piece of furniture cannot give someone a bookmark, so libreria clearly means bookstore.