I suggest just giving it to her without using magic, but if you want to give her the ring in a magical way I suggest keeping the magic simple so you can focus on telling her how you feel about her, and making the moment about her, not you doing magic.
Bobo switch a quarter for the ring, and load it into her hand. Have her squeeze tight as you tell her how you feel about her (lots of script options here--power of transformation, power of belief, etc.) and then have her open her hand for the reveal. It's still a magical way to give her the ring, but it puts the emphasis on her and how you feel about her, and leaves her with the ring in her hand--which is what you're after.
Good luck, my friend.