POINT 1
"Desu" is the polite form of the copula verb meaning "to be" or "is".
It is the verb used to describe two things as being equal:
A wa B desu.
POINT 2
There are several ways to say "I" in Japanese.
Watashi is the most common and polite one used by both women and men.
Boku and Ore is mostly used by men.