From Grand Grimoire:
Take a gold ring that is studded with a small diamond that has not been worn by anyone. Wrap it in a piece of green fabric and for nine days and nine nights wear it against your skin over your heart. On the ninth day, before the Sun rises, engrave the following word inside the ring: Scheva, with a new scribe or engraver.
Find a way to have three hairs of the person who you want to love you, unite them with three of your own hairs, while saying: “Body, that you could love me, that your desires could be as passionate as mine, by Scheva’s most potent virtue.” Tie the hairs in a love snare knot around the ring. Wrap the ring in a piece of silk, and wear it against your skin over your heart for another six days. On the seventh day, Fast. On an empty stomach, unwrap the ring and give it to the person you desire to love you.
If your ring is accepted then you can be certain to be loved by that person. If the ring is refused, rest assured that the heart of that person belongs to another and in that case, you should seek your fortune elsewhere.