This is the 8th most frequent Italian word.
della
"Della" means "of the" or "about the" (feminine singular) in English.
In this sentence, "della" is a contracted form of the preposition "di" (of) and the feminine singular article "la" (the), used here to indicate possession or association.
Ho bisogno della tua assistenza.
I need your assistance.
Here, "dalla" is a form of "della" where the preposition "di" is replaced by "da" (from), but it follows the same grammatical rule as a contraction before the article "la".
Lei viene dalla città di Firenze.
She comes from the city of Florence.
In this example, "della" again contracts "di" and "la," showing a specific topic or subject being referred to.