Let me start by saying that I very much dislike the “twin flame” label. Apart from the fact that what it represents has been hijacked by the “matrix” and turned into something which couldn’t be more misaligned with what it really is, I find the term itself too kitsch and even tacky.
I prefer to refer to a so called “twin” as a soul activating person. Somebody who comes into your life when you least expect it, to push all the right (wrong!) buttons so that your awakening becomes truly inevitable (unless you prefer to ignore your soul calling -something which is doable only until one day it stops being so)

The truth of the matter is that there are forces at play that don’t want your union, and “they” will do anything to keep you apart . This person carries a part of your soul, and any attempt at union will be blocked. One of the “twins” can unlock the door to union though – and although it is the hardest thing a human being can undertake, it is entirely possible.