Learn Italian: Le università apprezzano l'onestà dei giovani. - Universities appreciate the honesty of young people.

Words ending in an accented vowel, like università, are invariable. This means they keep the exact same form in both the singular and plural. To know it is plural here, you have to look at the surrounding clues: the plural feminine article le and the plural verb apprezzano.

Does the word onestà follow the same invariable rule as università?

Yes! Just like università, onestà ends in an accented vowel, so its plural form is also onestà. However, in this sentence, the singular article l' (which stands in for la before a vowel) tells us it is singular here.

Why does the sentence use dei giovani instead of just di giovani for 'of young people'?

Italian requires definite articles when talking about broad, general categories. So 'young people' in general is translated as i giovani. When you combine the preposition di (of) with the masculine plural article i, they merge into the articulated preposition dei.

Is giovani a noun or an adjective here?

In this sentence, it acts as a noun meaning 'young people'. Giovane is originally an adjective meaning 'young', but Italian frequently turns adjectives into nouns simply by putting a definite article in front of them.