This aria is a gem of the Italian verismo movement—dangerous, passionate, and over before the audience catches its breath. Download the score, practice that high B-flat, and remember the words of Loris: Love forbids you from leaving.
Go to IMSLP.org. In the search bar, type exactly. Because the aria is often catalogued as part of the full opera, you might get zero results if you only search the title. Instead, search for "Fedora (Giordano, Umberto)" .
Once you find the PDF, what are you actually looking at?