Twin Flame connection is a Spiritual connection that is beyond explanation.
Most Twin Flame reunions are unsuccessful because the individual people are not quite ready for the intensity of a Twin Flame union. It's usually one person who is a little more evolved than the other.
Twin Flame union is more intense than any other union. The intensity is at a soul level...not as much in the physical or even emotional bodies. It doesn't mean that there isn't a good attraction at those levels as well, but the strongest attraction is of spirit. This is one of the distinguishing characteristics of a Twin Flame.
The chances of meeting and staying with your twin depends on how evolved your soul is, and how much of your baggage from this and past lives you have cleared. The main reason twins have to separate after coming together is their individual emotional baggage.
In the presence of your twin, there can be nothing between you, nothing blocking your closeness. This means that everything comes up for healing that you haven't previously healed.
Soulmates can trigger the kind of sensation that feels like a Twin Flame connection. You have to remember that we have many many soulmates. But, we only have one Twin Flame.
With a Twin Flame, there is no doubt, no hesitancy. You have to look beyond the physical or outside influences and feel the connection on a soul level.
Even if you were separated for whatever reason, you will always know that he/she is "the one".