Dear Sir/Madam,
My name is Matheus Sobreira Wessen, born and raised in Rio de Janeiro, Brazil. I have a Bachelor's Degree in International Relations from the Pontifícia Universidade Católica do Rio de Janeiro, and I also volunteered to work as an interpreter for a British NGO in the Brazilian slums before graduating.
I believe I meet the requirements to help you. Not only am I a native Portuguese speaker, but I also used to work with both complex academic texts written in English and British colleagues. My fluency in the English language can be attested by my Certificate in Advanced English (CAE), which puts my proficiency at level C2, the highest of the Common European Framework of Reference (CEFR).
Hopefully I meet your standards. Please, feel free to contact me if you have any doubts.
Yours truly,
Matheus S. Wessen