He didn't believe her. Not that Wanda was particularly surprised by this. She knew what she was saying sounded crazy. She even questioned her sanity for thinking such a thing was true. But after weeks of contemplation, she knew it was true. She didn't just wish it was, it really was.
"Of course you have a mother and father," she replied softly. "A mother and father I'm sure that love you dearly. I am not claiming they aren't your parents, Billy. I'm only saying they aren't the only ones."
Wanda paused and glanced around for a ledge she could sit on. She was beginning to grow tired. Once a suitable ledge was found, she walked the few steps it took to get to it and rested. After taking a moment to get herself comfortable, she continued.
"Souls are a complicated concept. They are the essence of every living being, that I'm sure you know. What many do not is that they aren't burdened by the same restraints we are. Things such as time and space mean nothing to them. The soul of Billy Kaplan can easily be the same as the soul of William Maximoff because having two of the same soul present at the same time isn't an impossible feat."
Wanda's gazed dropped, shaking her head. This was too much for Billy to comprehend and was probably making him even more skeptical. "Your dreams are memories, Billy. How else would they be so close to reality? How else could they feel so real?" She lifted her gaze, looking into his face. "How can you explain the similarities between yourself and Tommy? How much you look alike without being related at all. The fact your talents and appearance mimic my brother's and my own? I truly believe you're a Maximoff, Billy. A Kaplan and a Maximoff."