How do you know if a guy wants to ask you to the prom and show him that you would like to go with him?

Its quite simple

whenever you are around him and other girls he is closest to you

he smiles when he looks at you

when you talk to him he doesnt talk very fast

To show him you would like to go with him talk about how you might not go to prom cause no ones asked you

and you doubt anyone will

good luck!