Anders gave you a very good answer.I just want to add that "she likes you" can be translated as " le gustas" ( the most common), "tu le gustas" (same meaning) and "le gustas tu" ( this one has the same meaning but used in specific situations). So i'm gonna explain the last one. It's commonly used when the topic is about 2 or more choices. Example: -I wanna date Kate but I think she likes Michael- -she likes you- -Quiero salir con Kate pero creo que le gusta Michael- -Le gustas tu-

Think of it this way: Let's ask ourselves the question: Why do we like things? The answer, of course, is that the things that we like have certain "likeable" qualities that MAKE US like them, so in other words, I like music because it (has qualities that) MAKE(s) ME like it... So, let's say you like classic films = team gustan las películas clásicas = classic films MAKE YOU like them She likes fast cars = le gustan los autos rápidos = fast cars MAKE HER like them But if she likes you, it means YOU have certainly qualities that MAKE HER like you = you make her like you = le gustas (tú) The same if she likes me = le gusto yo The same if she likes us = le gustamos (nosotros) Based on the above logic and examples, it should make sense to you now :) It's true that most examples will be either "gusta" or "gustan", but not whenever someone likes you, me, us, or even more of you in peninsular Spanish (eg. she likes "you guys" = le gustais vosotros) Hope this helped! :)