Farfalle nello stomaco literally translates to "butterflies in the stomach." While the individual words are common, this idiomatic expression is a beautiful and universally understood way to describe the feeling of nervousness or excitement, especially in love.
In the song, Elisa uses this phrase to convey the intense emotional and physical sensation of being with someone special. It perfectly captures the fluttery, exhilarating feeling that love can bring, making it a relatable and enticing phrase for learners.
Elisa's "Con te mi sento così" is a love song about how one person changes the way she feels about herself. Without him she is "fragile" and "piccola" (small): "È che mi sento fragile / Se qui non ci sei tu" (I feel fragile if you're not here). With him the weight goes: "Oh, come una piuma leggera" (like a light feather), and "niente può fermarmi, tradirmi, spezzarmi" (nothing can stop me, betray me, break me) as long as she knows he'll be there.
The last verse turns calm. "I giorni sono numeri / Il tempo qui non c'è" (the days are numbers, there's no time here), and "Nel buio di quegli angoli / Io non piango più" (in the dark of those corners, I don't cry anymore). "Le cose sono semplici / Da quando ci sei tu" (things are simple since you've been here) sums it up: the song is about the plain relief of feeling safe with someone.