I used magic and deception throughout the entire proposal process. My (then future) wife and I went ring shopping and we found the ring. I knew it, I could see it. She was hooked. We left. The next day, my wife returned to the jeweler with her family to show them her ring. She was informed that there had been a few people looking at it.
As soon as I worked next (in the nearby city where we had gone ring shopping) I stopped by the jeweler. I put a deposit on the ring and had it held for me until I could scrap together the cash to pay for it. A few days later, I had gathered up enough cash for a big down payment. I took the ring home with me. On the way home, I stopped by her apartment to tell her that I had to confess something. I told her I had gone ring shopping that day and that her ring had been sold earlier in the week (this made sense after she heard people had been looking at it.) I told her that we had the option, when I could save up the cash to pay for the whole thing, to order the ring in from the manufacturer. I gave her a made-up time frame that made sense and enough "facts" that I couldn't be lying, all the while her ring was in my pocket.
While all this happened, my (soon to to be) wife and I were planning a trip back to my home in South Dakota (where we met.) My mind was in overdrive. As the day drew near, I told my wife that I saved up enough to go order her ring. This I "did" a couple days before we left (instead I simply went to work early.) I came back and told her that the jeweler had called on the ring and figured it would take about three or four weeks until it arrived. This meant (to my wife) that her ring would come sometime after we got back from South Dakota. Again, the ring was hiding in plain sight (this time in my luggage.)
In South Dakota, after a 19 hour trip, we arrived at my house. We spent time with my family, met up with some friends, and relaxed for a couple days. One of those days I took my wife for a walk (nothing out of the ordinary for us except the South Dakota location.) In a park on the Missouri River, we sat down at a park bench and talked for a while. As we talked, I asked if she would like to see real magic. My wife, her favorite hobby being trying to figure out my magic tricks, was eager to have something new to figure out. I pulled my cards out of my pocket, took the clip off, and pulled the cards out of the tuck case. I had her ring in finger palm and dropped it into the tuck case as I pulled the cards out. I set the clip on the cards, saying that I did not need my cards for this trick, only the box. My wife looked confused, and became more confused when I picked up the empty box and lightly shook it so she could hear something rattling inside. I then turned the box over, dumped its contents into my open hand, and got down on one knee. It was real magic. The trick was just the cover for the moment. The real magic had nothing to do with the trick.
Yes, she said yes. We have been married for a little over a year now. My wife still chuckles about the magic trick she didn't see coming. I did this because it would work. Don't do magic for something like this unless it too is right. Just because you like magic doesn't mean that this will be the right way to go. It likely isn't. IF you decide to carry on, let me give you a couple pointers.
1. Use magic, but but don't make it about the magic.
2. Make sure that you do MUCH more than just the trick. Planning is essential.
3. Magic can enhance the moment, but once the moment begins, it needs to get out of the way or it will kill the moment.
4. Make sure you can do whatever it is you are going to do flawlessly. You cannot afford a mistake at a time like that.
5. Make sure that your have thought through the "Big Picture" over and over again. It has to make sense. The whole event needs to be smooth. If not, you need to back out and do something different.
I am the exception when it comes to this. I would not recommend doing this to most people. The most crucial thing is figuring out if it works FOR YOU AND HER. You need to be sure, don't just assume.