From the lyrics of Belinda's "Bella Traición" ("Beautiful Betrayal"), you might detect bitterness:
Lo siento si agoté la ilusión
I'm sorry if I ran out of hope
[Caption 12, Belinda > Bella Traición]
The verb agotar means "to exhaust; to use up; to run out of." It's helpful to remember that the noun gota means "drop" as in "a drop of water," (una gota de agua). The verb agotar stems from squeezing out every drop of something.
Now, you might ask why we didn't translate ilusión as its seemingly simply English cognate "illusion." After all, we might translate ilusión óptica as "optical illusion" and falsas ilusiones as "false illusions." But the Spanish ilusión has meanings you don't find in its English sound- alike. Check out these examples:
No te hagas ilusiones.
"Don't get your hopes up."
Su ilusión desde pequeña era ser actriz en Broadway.
"Her dream since she was little was to be an actress on Broadway."
Cuando pierdes la ilusión...
"When you lose heart..."
All of these examples employ "ilusión" as a synonym closer to "esperanza; sueño" or "hope; dream" in English. That's what we thought Belinda's lyrics were aiming to convey. Listen in to the song's refrain:
Porque sin ti no hay presente ni futuro, sálvame
de esta bella traición que me mató mi ilusión.
Because without you there's no present nor future; save me
from this beautiful betrayal that killed my hope.
[Captions 9-10, 19-20, 27-30, Belinda > Bella Traició]
Now, before we move on we must note that ilusión has a third meaning: "excitement; thrill," as in these expressions:
Me hace mucha ilusión
"I'm really looking forward to it; I'm thrilled."