Yeah of course you should believe in Bitcoin because it can allow you to make some money and that can be really nice. I am believing in Bitcoin and will continue to do so if I can make money with it.
Once someone starts earning it he himself will start believing it, because before someone can earn it they think it is really not something achievable or it is something not for us or for the ones who are superior, but that is not true, bitcoin is for everyone and everyone can have it they work for it.
Yes that is going to make him believe more in bitcoin once a bitcoin person started to experience earning in bitcoin or experience to have some transactions in bitcoin. He is going to love how fast transactions and easy are happening in bitcoin. And that is going to make his belief even stronger to bitcoin because of those things.