@ziawj2,
The English is pretty good.
A few minor edits (the changes are
bolded):
Dear Lucy
,
Thank you for
the beautiful flowers. They are gorgeous and I really appreciate your kindness. I not only enjoyed
the flowers, but also the delicate vase. I shall
forever remember this gift as one of the most precious things in my life. I hope to have the opportunity
to reciprocate sometime.
If you ever have time to visit me, I would be very happy to see you.
Thanks again for your lovely flowers. Please give my kind regards to your family.
Yours truly
,
Jiang Mengyun
Do you and Lucy share a common culture? (Chinese, for example?)
If Lucy is Western (American, British, etc.), I'd encourage you to take things down just a notch. It's a bit much to describe a vase with flowers in it as "one of the most precious things in my life," and that might ring false to Lucy. You could say, perhaps, "I shall forever remember your thoughtfulness."