When I looked up the word "fulfill" in the SpanDict, I found "cumplir" and a few other translations, but I didn't find "llenar," which can also mean "fulfill."
Example: In an interview about a movie directed by Verónica Pamoukaghlián, the director said this: "Lo más lindo de mostrar la película es que la gente se engancha enseguida: se emociona, se ríe y muchos lloran también. Esto es lo que más nos llena a quienes la hicimos, llegar al corazón de las personas de ese modo." The second sentence here means "This is what is most fulfilling for those of us who made it..."