i can only hope that the rate will rise until reach $800 when is halving, and after that still rise
Yes it will rise to $800, but it will be short lived because people will sell their bitcoin as fast as possible.
If bitcoin got sold a lot, then the price will drop again.
Exactly, also at that price who will buy those sell orders. If you know how to ride the wave properly though you can profit by selling at the first sign of sell walls. From there on, altcoins will rise.