Learn Hardcore Italian: Se l’oroscopo ti interessa, te lo invio subito. - If the horoscope interests you, I’ll send it to you right away.

Italian interessare works like English “to be interesting to” (or Spanish gustar). The thing that interests (“the horoscope”) is the grammatical subject, and the person is expressed with a dative pronoun (ti). So Se l’oroscopo ti interessa literally means “If the horoscope is interesting to you.”

Why is interessa singular instead of interessano?

Because the verb agrees with its subject, which here is l’oroscopo (singular). If the subject were plural, e.g. i libri, you’d say Se i libri ti interessano.

Why use ti instead of a te in Se l’oroscopo ti interessa?

Clitic pronouns like ti replace full prepositional phrases (a te) for brevity and fluidity. Se l’oroscopo ti interessa is more idiomatic than Se l’oroscopo interessa a te, though both are correct.

In te lo invio subito, why is it te lo instead of ti lo?

When ti (indirect object) combines with another clitic (lo, the direct object), it changes to its tonic form te for easier pronunciation. So you get te + lo, not ti lo.

What is the order of pronouns in te lo invio?

Italian clitic pronouns follow this hierarchy:
1) Reflexive (mi, ti, si, ci, vi)
2) Indirect object (mi, ti, gli, le, ci, vi, loro)
3) Direct object (lo, la, li, le, ne)
In te lo invio, te (indirect) precedes lo (direct).

What does subito mean, and can I place it elsewhere?

Subito means “immediately” or “right away.” Its neutral position is after the verb (te lo invio subito). For emphasis you can also say Subito te lo invio, but putting it before the verb in everyday speech is less common.

Could I say te lo mando subito instead of te lo invio subito?

Yes. Mandare (“to send”) is more colloquial; inviare is slightly more formal or technical (e.g. in emails). Both te lo mando subito and te lo invio subito are perfectly natural.

Is Se l’oroscopo ti interessa interchangeable with Se sei interessato all’oroscopo?

They express the same idea but use different structures:

Se l’oroscopo ti interessa uses the verb interessare
- dative pronoun.
Se sei interessato all’oroscopo uses the adjective interessato
- preposition a (elided to all’).
  Both are correct; the first is more direct and common in casual speech.

Why is it written l’oroscopo with an apostrophe instead of il oroscopo?

When the definite article il precedes a vowel-initial word (here oroscopo), Italian drops the vowel i and replaces it with an apostrophe: l’. This elision smooths pronunciation: l’oroscopo instead of il oroscopo.