Dear Miss Kuroda
Hereby, I would like to express my warm gratitude for the great assistance you did during my permanent visa application process. I am sure without your assistance I could never get it. Surprisingly, I get it in less than four months. 
In fact, I was impressed with your up-to date immigration knowledge and appreciate about carefully read my resume and other relevant document.
Definitely, I will recommend you to all of my friends who have immigration issues.
Wish you the best