Hello, my dear (ім'я друга)!
First of all I would like to thank you for asking me. I'm very happy, because you has invite me to a football match. I agree to your invitation, because I really want to go with you to the soccer match and also I like it. Besides, after the match, we can go to the cafe and eat something tasty! Also I will buy you your favourite ice cream.
See you soon.
Your sincerely,(власне ім'я).