I met this guy whom I found striking but after having a couple of conversations with him as friends, I realized that I couldn't flirt with him even when I wanted to. I guess you can learn to be passionate even if there is no chemistry at first because we ended up dating sometime later, but it took time and at first, it was very awkward and almost weird. Give it the time it needs, don't get bothered with the awkward slow progress and you'll get there.