If you believe a fortune teller's prediction about your future in toto, it means you accept the truth of everything he says. In toto means "all together" or "without exception."
Use the adverbial phrase in toto when you want a formal way to say "entirely." You might come across in toto in a legal document or a work of literature, or you could explain how you took your college adviser's recommendations in toto, and signed up for every class she suggested. In toto is Latin, from the root word totus, "whole or entire."