When Portuñol speakers try to communicate with Brazilians, they often get a confused look when they unwittingly use a Spanish word that has a similar-sounding equivalent in Portuguese. Despertar(se) is one of those words. To wake up in Portuguese you say acordar NOT despertar. Like in Spanish, acordar in Portuguese can mean to agree or reach an agreement. But its most common definition in Portuguese is “to wake up.” That’s right, despertar(se) just isn’t used in spoken Brazilian Portuguese to say “wake up.” So don’t use it.
Also, acordar in Portuguese doesn’t mean “to remember,” even though it looks a lot like acordar(se) in Spanish.
English: I woke up at 3 in the morning and couldn’t go back to sleep.
Spanish: Me desperté a las 3 de la mañana y no pude volver a dormir.
Portuguese: Acordei às 3 da manhã e não consegui mais dormir.
English: I don’t remember.
Spanish: No me acuerdo.
Portuguese: Eu não me lembro.