I once read about how twin flames can trigger physical sensations and even health changes. With my true twin, I noticed weird synchronicities in my body, like heart palpitations or bursts of energy at random times, especially when we were apart. It was like my body was responding to the connection on a cellular level.
With a false twin, though, I felt more drained and often got sick. So, maybe pay attention to what your body tells about this person. It might offer clues you hadn’t considered before.