NAMK, this is a silly question. When you say "you" without defining it, it automatically refers to your perception of me. Therefore, if you are reading this, the word "you" refers to the sentience that originated this message (at least, I think it does) and therefore, it is inevitable that *"you" exists.
Why? Because even if this reality is just your dream, then you wrote this, and you exist. If it's my dream, I wrote this, and I exist.
If noone exists to dream this, then we are the null. We are still a sentience, even if there is no sentience.