how to write a formal and simple feedback to reply?
when i got a mail from someboby, what should i give a feedback to him or her? usually i write "i've received your email. and thanks for your kindly reply. i'll check it and give you a feedback asap." how about this?

Question

how to write a formal and simple feedback to reply?
when i got a mail from someboby, what should i give a feedback to him or her?  usually i write "i've received your email.  and thanks for your kindly reply. i'll check it and give you a feedback asap."   how about this?

Answer

It would be better to write.
I have received your email. 
Thank you kindly for replying/ thank you for your reply/ thank you for replying. ( I don't think you mean a 'kind reply' ( 'kind' as an adjective here would mean warm / showing understanding or sympathy)
I'll check it and let you know/ give you feedback/ answer you asap.

Answer

Thank you for your email. Please expect a response from me as soon as possible.

Answer

If I were writing it myself, I'd say:

I received your email I will look into it and get back to you shortly.

There are many right ways to say this differently, but this is my usual choice of words... :)

Đừng bỏ lỡ cơ hội học ngoại ngữ ngay tại nhà. Hãy xem danh sách các gia sư ngôn ngữ giàu kinh nghiệm của chúng tôi và đăng ký buổi học đầu tiên ngay hôm nay!