If Your Answer Is Yes
Before you accept his request, ask yourself if you are really interested in this guy and ask him what he wants from you. And if you have confirmed your feelings for him, you still have to figure out what he has in mind. You can directly ask him what he means and whether he has invited other friends. Make sure you are comfortable with his intention, and then you can say "Yes, I'd love to", and ask for more details of the date, for example, the time and the occasion, to get prepared for your date.
If Your Answer Is No
If you want to turn down the date, explain your reasons clearly. Now that you have decided, no matter what he says, don’t compromise. You don’t have to make up the reason or try to be nice. It is okay to be frank with him about how you feel about him.. But but you have to express your feelings properly. You don’t have to prepare a long speech to explain in details why you don’t like him because in that way, he may feel awful about himself.
If Your Answer Is Maybe
If you are not sure if you are into him or not, take your time and think it over. Don’t rush to decide. When he asks you out, you can tell him you need time to consider it. Bur remember, try not to let him wait too long. Then you can choose to seek advice from your friends or family. Hanging out as friends and getting to know him more may also help you to give a definitive answer.