Dear xxx,
I want to introduce to you the bearer of this letter, my younger sister, xxx. She is going to take one-month training in xxx University. She is a lively and lovely girl, whom I am sure you will like to make friends with.
But since it is the first time she goes to a strange city, I am a little worried. I would be ever so obliged if you would be so kind as to meet her at the railway station and accompany her to xxxx University to register for the course. She will have no problem with her accommodation. I hope it will not cause any inconvenience for you. By the way, my sister’s mobile phone number is xxxxxxxxx.
Thanks very much.
Sincerely yours,