Thank you so much today. It was truly helpful. I regret that my stay this time has ended so early, but I promise I'll imvite you out for a dinner or something during my next visit, which will be a longer one.
Thank you very much. You were a big help today. This time, my stay is too short to go for dinner (lunch) with you but I will stay longer at my next visit. So let’s have a dinner (lunch) together!
Thank you very much for today. You saved my day. It's such a short stay this time but next time I'll stay longer. So, we should go for a meal or something then!