"She liked it immediately."
Translation:Le è piaciuto immediatamente.
"Piacere" is non transitive verb and it always wants "essere" as auxiliary verb. In English the sentence is "I like ice-cream" --> I is the subject, ice-cream the object. In Italian the sentence is "Mi piace il gelato" = "Il gelato piace a me" (The ice-cream is liked by me). Gelato is the subject. In this particular sentence would be "It was liked by her immediately". If you use this construction even in English "to be" is the auxiliary verb.
So where's the "it" in this?
Without the actual subject mentioned, this could be as well be "She liked him immediately", right?
And where did the "a" disappear? Do you not use it if the subject of piace is not explicitly mentioned?