Dear Mr。x,
Thank you very much for hosting such a wonderful dinner party and inviting me to come along。
I thoroughly enjoyed meeting so many new friends during the party and must have spent the most memorable evening in my life there。
Your hospitality is far too heart-felt and I must congratulate you for being such an excellent host。
I look forward to repaying this generosity of yours in the not too distant future。
With warm regards,
yy。