You have promised to play tennis with you friend every week, but you are not very good at it.
EXAMPLE:
A:I'm not very good at tennis, you know.
B:Don't worry! We are playing for fun. Just try and you'll see you can do it.
A:I haven't played tennis for a very long time.
B:Well done! That was a very good ball! You see you can do it!
A:I hope so. I enjoyed playing tennis with you. See you next week.