This is the 3761st most frequent Portuguese word.
be
The word "be" does not exist in Portuguese as a standalone term.
Here, 'sou' derives from 'ser', meaning 'to be' in the sense of a permanent state or characteristic.
Eu sou feliz.
I am happy.
Here, 'estou' derives from 'estar', meaning 'to be' in the sense of a temporary condition.
Eu estou cansado.
I am tired.
Here, 'será' derives from 'ser', used in the future tense to indicate something predicted or expected to occur.