Allow me to explain the opera's plot, then. This particular aria is from Lucia di Lammermoor, one of Donizetti's most famous works. The titular Lucia is in love with Edgardo di Ravenswood, but this is complicated by two things: her brother loathes the di Ravenswoods and will stop at nothing to end their relationship, and Lucia is betrothed to another.

[saber why did you get him started...]