Young people come to me all the time and ask, "How do I know so and so is the person I'm supposed to marry?" There is no magic formula. It's challenging to figure out. But I've concluded probably the best way to know someone is supposed to be your life's mate is not to think about the person you can live with. It's much more important to think about the person you can't live without!
Imagine life without that person. Imagine the years passing by without being with this person. Imagine yourself at the end of your days, looking back over you life and regretting not having lived with that person. If your heart becomes very sad with the thought of not living with that person, that person is probably the person who should be your life's partner!
Again, don't marry the person you think you can live with. Marry the person you can't live without.