The very first line of dialogue spoken in this new TV spot for Star Wars: The Last Jedi is something we're hearing for the first time; Luke asking, "Why are you here?" This line was obviously carefully selected to keep the mystery of Rey's lineage a mystery since it could literally be the first thing Luke says to her after retrieving his old lightsaber, or it could be the second question he asks after, "Who the hell are you?"
The fact that it could go either way is very exciting. Lucasfilm has been tight with footage, dialogue, and plot points from this film as they're likely protecting an "I am your father" level twist somewhere in the third act of this flick. Protecting a twist that big in this day and age is going to be a nightmare, so I'd recommend checking this movie out within the first 24-48 hours of its release if you want to preserve any sense of surprise.
I vow here and now not to release that information on this website, even if it thoroughly pisses me off. I'm not gonna be a "Dumbledore dies on page 606" guy, even if they do decide to make Luke go to the dark side. Seriously, if that happens, I will be very angry and upset, but I will not spoil it for you. We'll talk about whatever the big twist is in January. I vow to keep embargoed until then, to give you at least one website you can visit without having to worry about everything being spoiled for you. Scouts honor.