How can I tell this to a guy I’m talking to?

So I been talking to this guy for a couple weeks. Well we dated before and in these couple weeks he’s proved himself. He’s talked to my mom. He’s asked his mom to give me a second chance and she did. And so on. Well we agreed to taking things slow. Well I want to make things official but at the same time I don’t know. And we agreed not to bring sexual stuff into it. And it’s got to where I’m starting to want to bring into it now. I want to tell him but I don’t know how. I’m scared to tell him.