English is not my first language, and I am concerned that my statement of purpose might contain some grammatical and punctuation mistakes that neither Microsoft word nor I can see. What is the best way to overcome this problem, and to what degree does this affect the admissions committee decision putting into consideration that English isn't my first language?
P.S. I don't have any native English-speaking friends and I don't trust companies or online sites to see my statement of purpose to check its correctness.