Breakdown of La squadra vince, perciò ne siamo fieri e piangiamo di gioia.
essere
to be
e
and
di
of, from
la
her/it (direct object)
Questions & Answers about La squadra vince, perciò ne siamo fieri e piangiamo di gioia.
What exactly is the "ne" replacing in this sentence?
It replaces di questo (of this) or del fatto che la squadra vince (of the fact that the team wins). The adjective fiero requires the preposition di (essere fiero di means "to be proud of"). When referring back to a whole situation or preceding clause rather than a specific noun, ne acts as a "propositional pronoun" to mean "of it" or "about this fact".
Does the "ne" before "siamo" cause the adjective "fieri" to be plural?
No. While ne does trigger agreement when used as a partitive direct object in compound tenses (like Ne ho visti tre), that rule doesn't apply here. Fieri is masculine plural simply because it agrees with the subject "we" (noi). The ne here is an indirect object (meaning "of it") and does not affect agreement.
Could I use "quindi" instead of "perciò"?
Why do we say "piangiamo di gioia" instead of "con gioia"?