Getting married to my best friend? but can we leap this one hurdle?

I was recently asked in a almost scared way by my best friend(we will call her Betty) if I would consider marrying her before she goes into the army in january. I said yes of course becuase I love her to death, but in the 10 years i’ve known her we’ve never gone too far intimately, and now that we’ve pretty much decided this it seems like there is no want for my true love from her. She wont show me that at all, and i know we’ve never been intimate too much, we still have a little bit, we just always stopped each other because we didnt want to ruin our great friendship. But now I’m trying to be romantic with her, spending all the time I can with her, whispering to her I love her, sleeping right by her side, but she will not show the slightest bit of intimacey. And when i told her I promised to love and care for her forever she said we needed to stop talking about it because it was making her cry. Basically my problem is this, we have both pretty much decided we will get married, but there is no romantacism between us, what do I do, I want to just kiss her so bad, but how will she react, if she isnt responding to me trying to be romantic, than how will she react to that. I cant marry somebody I have no romantic spark with, and the only time we have that spark is when were drunk, but i need that all the time from my wife. So when i step back i think this isnt gonna work out, but I LOVE HER WITH ALL MY HEART, and I truley do want to spend the rest of my life with her, but how do I make her understand that we need to be friends AND lovers if were gettin married. I just dont want to come off like i’m tellin her i want some action, because that really doesnt matter to me, I just want to kiss her and look her in her eyes and tell her I will always be hers and only hers. SOMEBODY HELP, what do i do? what do i say?