Smoke cleansing the deck, certain spread, or other methods to encourage a super-accurate answer?

I'm going to ask whether I should ask out a dear friend of mine. I really value this friendship and I think he could be the one. But if it blows up in our faces, I lose an important friendship. So I really want to get it right.

Does anyone have a method they like to cleanse the deck, or does anyone have a spread about love that they've found to be very accurate?

Thanks!