I am writing this letter to express my sincere gratitude to you for your help and kindness.
Once again, thank you for your help. I hope that I will have the opportunity to return your charming help.
I am 身份 who 与被建议对象的关系 . Generally speaking, is/are quite good; however, I have some better suggestions for you.
Firstly, it would be greatly appreciated if you could 建议一 because 原因一 . Moreover, 原因二 , so it is advisable for you to put emphasis on 建议二
I hope that you will find these suggestions helpful. Thank you for your reading and patience.
I am writing this letter to recommend you —— . I know 被推荐对象 well, because —— .
The primary factors for my recommendation are as follows. For one thing, 理由一 . For another, 理由二 .
I hope that you will find —— wonderful and worthy of attention.