You will never know. Dating in Brazil is just another way to spend free time alongside reading or watching movies. It often happens just for fun and therefore not treated too seriously. The status of girlfriend or boyfriend doesn’t necessarily imply your partner is absolutely in love and eager to spend their whole life with you.
Brazilians also are pretty passionate and impulsive. So once they meet somebody who is nice and good to spend time with they are up to a relationship. When in other countries it takes a long process of thinking everything over and analysing the need to approach a person you like with a suggestion to date, in Brazil it happens as fast as a week goes. Since this is a thing all over, brazilians are ready that their relationships won’t last long and therefore don’t give too much value to the status of girlfriend or boyfriend.