I don't have to be native to master English, I might have been studying in English through my entire life. In these cases, we judge by standardized tests. I have scored 109/120 in the TOEFL iBT, with a writing score of 30/30, which is maybe a higher level than that of the natives. I have taught people English for so long, so I have the experience to take care of your job. Just contact me for more details.