You might be asking a bit much of him, this technology stuff isn't super easy for everyone.

In two easy steps:

$ ./bitcoin-cli signmessage 1GMaxweLLbo8mdXvnnC19Wt2wigiYUKgEB "Digital signatures are to scammers as garlic is to vampires. I am hn user nullc, but you are not Bitcoin's creator."

$ ./bitcoin-cli verifymessage 1GMaxweLLbo8mdXvnnC19Wt2wigiYUKgEB "HJ0VgbIY9BAud6MiZ4Qh0KSwhmA7gwkFm07tjPJeHsYNcj5oIAVlVR2JnKTF7EjqTWEaD9QbAPzk8QII8QJxW4s=" "Digital signatures are to scammers as garlic is to vampires. I am hn user nullc, but you are not Bitcoin's creator."

true