Will my nail reattach its self as i have ripped it off half way with a fake one on top of it?

No. You are better to clip it off and let nature take its course to grow the nail outward. Don't cover it with a fake nail at all, that hinders air from getting at it.Will my nail reattach its self as i have ripped it off half way with a fake one on top of it?
No, but a new one *might* grow in its place. Just keep ointment and moisturizing oils on it, and don't pick at it. You may have destroyed some of the nail bed. When it comes back, it will probably come back thicker and slower.Will my nail reattach its self as i have ripped it off half way with a fake one on top of it?
It is very unlikely it would reattach. If it did, you would soon have an ugly distorted nail and the unattached part would soon have an infection underneath.
No. Your fingernails are not alive; only the base that it grows out from is alive. (Kinda like if you cut your hair and changed your mind, it wouldn't repair itself if you taped it back on.)