I can only contribute this: When someone is genuinely divinely for you - you KNOW, instantly. And yes, you "fall in love" instantly because the energetic connection cannot be grasped with the mind, it just happens, you are hooked up energetically with another being and - until the lessons are learnt you will both be "chained together" and boost each other's evolution with gigantic steps.
Can feel claustrophobic and hugely triggering for the ego, but there is no way around - god does it in the name of True Love. And, besides inexplicable "heart-bond", it will reflect back to you all the ways you do not love yourself, like a perfect mirror. :)))
If that was only a "lesson" in the chain of life-lessons - the bond loosens when the lesson is learnt,.. and you'll feel your heart free to move on to the "next lesson".
If your ego rebels to such order of things - the lesson will be repeated again and again and again :)
So, yes, you KNOW instantly who is the right one for this moment in the journey, but it doesn't necessarily mean that it will be this one for the rest of your life.
Have you lived something like this? Energetic connection that is unbreakable by ego's resistance strategies?