What do you say when a guy says he wants you?

It depends on your feelings as well as his maturity level. If you are not interested in having a relationship with him and already are in a committed relationship yourself, then kindly explain that you are happy with your current boyfriend. Do not make any statements which might seem like an attack or complete rejection. If you are interested, then tell him that you are open to dating and but that there are boundries which must be respected. You will know what your own boundries are - Find out what his boundries are if they are way beyond what you are comfortable with then tell him - He may be willing to compromise. Make his willingness to compromise a condition if necessary. Dating can be very difficult for even adults - We all have to learn our way around it. There is a saying in Dance. "The man proposes, the woman disposes."