What makes a twin flame turn into a runner

 Why do they run from such intense and heavenly love and oneness? Why do they say no to love and turn their back on the best thing that could ever happen to them?

They become the twin flame runner because of FEAR. You may think that surely the love overrides the fear, but such intense love actually causes the twin flame runner to feel incredibly unworthy and frightened that if they surrender and allow this love into their life, that it may be taken away. They fear being left with nothing, because getting close to you would mean they let go of their "normal life" in terms of their old ego identity and old beliefs about how the world operates and what is true. You have opened your twin flame up to seeing life in a new reality, the truth of soul.

The connection is a gift from God, because they are not believing in themselves and are insecure, they are certain that God will just as easily take their twin flame away from them. They can tell this connection is a test, but they mistakenly conclude it is a test to prove if they are good enough for true twin flame love or if they aren't good enough and will fail. They fear that if they aren't good enough and fail, then God will show them they aren't good enough by taking the love away.

It is the fear of REJECTION and not belonging that frightens them the most because subconsciously we know we are all connected, all as One in soul, but the ego believes, because we inhabit a physical body, that we are separate and not belonging and one. Subconsciously your twin flame thinks this is a final test (and it is of sorts) but their lacking in self-esteem so believe they will fail the test, so the run away, pretending to themselves that they don't even want this anyway and that it doesn't matter. They are trying to go back to their old "normal" life because they think they can get over this love eventually because they are sure they cannot really have it if they go for it