De ley
"Definitely", "for sure", "no question" — and sometimes "you have to", when the law in question is social.
Related lesson: Ecuadorian Spanish: A Survival Guide.
Hear it in context
De ley que llega tarde, siempre le pasa lo mismo.
He'll definitely be late — it's always the same with him.
—¿Vienes al partido? —De ley.
'Are you coming to the match?' 'Absolutely.'
De ley tienes que probar el encebollado antes de irte.
You absolutely have to try encebollado before you leave.
What It Actually Means
De ley asserts certainty. Depending on where it sits, it means “definitely” (de ley que viene), “of course” (as a standalone answer), or “you simply must” (de ley tienes que ir). What unites the three is that the speaker is not entertaining the alternative: de ley closes a question rather than answering it.
Where It Comes From
Transparently from ley, law — “by law”, “as a matter of law”. Spanish has always had de ley in the legal and metallurgical senses (oro de ley is gold of guaranteed purity, and una persona de ley is someone thoroughly decent). Ecuador took the guarantee and dropped the gold: what is de ley is what you can bank on. Peru and parts of Bolivia use it the same way, but in Ecuador it is a conversational reflex, not an occasional flourish.
How Natives Use It
Constantly, and mostly at the front of the sentence. The commonest frame is de ley que + indicative — note that the indicative is the point, since the speaker is stating a certainty, not a wish: de ley que gana, never de ley que gane. As a standalone reply it is enthusiastic agreement, the Ecuadorian counterpart of Mexico’s sale or Spain’s venga. Young speakers stack it: de ley, de ley, ahí nos vemos.
Common Pitfall
Do not use it in writing that has to sound formal — an email to a ministry that says de ley que le enviamos el documento reads like a text message. And do not confuse it with de ley in the older sense: un man de ley is not “a definite guy” but a thoroughly reliable one, which in Ecuador is high praise and still current.