Will FWB ever turn into a relationship?

He's 31 i'm 24. He told me he's not ready for a serious relationship yet and so do it. We liked each other. We like spending time with each other. He just said he's not looking for a relationship that's going to last only 2-3 years, he wants a relationship that can last hopefully a lifetime. I understand that and I feel the same way too. We've been hanging out for about 3 months now. I was just wondering if this will ever turn into a serious relationship.