By Yours sincerely, Language schools

Hi all! I have written this to the best of my ability. I'm pretty secure about the language part, as I'm bilingual, but it's the culture part that I want to check works. Some stuff I need to put in there, like the reason for the GPA - it's part letter, part appeal. But, this is...

Dear Benny, Good Evening! Regarding to what you say, I also confuse of that. I learn from my teach in language school, she also told us the same like your explanation: if you know the person, you can use "Yours sincerely", and if you do not know the person, you should use "Yours...

In the meantime, I look forward to receiving your application, and remain, Yours sincerely, This "remain" in a letter (from a language school) looks strange to me, but is this natural English?

hey everyone, this is my motivation letter for an exchange program. i actually finished it, but i m not quite sure how it sounds like. i can imagine that you are all busy, but maybe someone still can help me with checking for mistakes and style. i would appreciate it a lot. Dear Ms. ***: ...