Translation:I have decided to tell him that I love him.
I find it funny that an earlier sentence in this lesson was, "Voglio di dirgli che lo amo."
That sounds strange to me. As far as I learned, after 'volere' verb goes directly, without a proposition. So, in my opinion, this sentence should be: "Gli voglio dire che lo amo"
The previous question was 'non dirli la risposta' for 'don't tell him the answer', but now it's 'dirgli'. Is there a rule here to help the confused?
dire a lui Ho deciso di dire a lui che lo amo. = Ho deciso di dirgli che lo amo.
"lui" is the personal pronoun which is generally the subject of a sentence. him, her etc. are the object pronouns (in Italian you have an direct object pronoun and an indirect object pronoun. For both exist an accented and an unaccented type.
I answered - I have decided to tell him that I love it, and it was accepted.
I didn't got "to" as an option in the words I could use and got it wrong for not using "to" in my answear. This is not the first time something like this happens to me.
Couldn't this sentence also be translated: I have decided to tell him that I love it?
"I had decided..." is past perfect. "I have decided..." is present perfect. Here's an explanation of the difference: https://www.espressoenglish.net/difference-between-present-perfect-and-past-perfect-in-english/
I have decided to tell him that I LOVED him. This is an example of INDIRECT SPEECH (ENGLISH) and both verbs are in the past tense.
The sentence would be different in English, too. "I have decided to tell him that I loved him" means that I don't love him now.