Maybe you feel fluent in informal Spanish but you don’t feel ready to get a certificate because of the grammar: “I have no idea about verbal tenses…”, you feel.
Learning a language means to integrate all its nuances which embrace speaking, reading, writing and listening (of course!) but mastering a language also includes being able to express yourself in formal and informal scenarios.
I will teach you how to express yourself depending on the context you are in (because it’s not the same to ask for the bill in a Spanish tapas bar than in a fancy restaurant, right?)