i asked out a friend. I don't think they understand that this is something I did with romantic and not platonic intent. How do I make that clear?

I asked out a friend of mine who I've been trying to ask out for a while now to grab coffee next week. They said yes but I don't think they got the more than platonic intentions I had, they seem kind of oblivious to it (or are just hiding it well). I can't flirt if my life depended on it, how can I convey my romantic intent without just... saying it outright?

idk if I'm giving enough context or detail here but feel free to ask if you need