Honorific__ ,
Via the assessment of the statistic between the business of your company and our company,we are in honour of informing you be evaluated as the "Diamond Class Client of XXXX 2008”
For assessment task of the clients,Our company via evaluating the statistic of the business between we and our clients,setting up nine classes together,they are descending as followed：
Diamond Class,Platina Class,7 Stars Class,6 Stars Class,5 Stars Class.4 Stars Class,3 Stars Class,2 Stars Class,and 1 Star Class.
級(jí)別這里翻譯成Class 比Level更地道~以上是嚴(yán)格按照樓主的意思自己翻譯的,