When would I know that I met the right girl in my life? Never had a girlfriend so I don't know?

How do I know who the right girl is that I will spend the rest of my life with. I never had a girlfriend and I so far have no evidence I met the right girl. I had many girls I liked, all whom I never really spoke to. One I did, but turned out she's really mad at me. I don't know.
When would I know that I met the right girl in my life? Never had a girlfriend so I don't know?
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