First of all, the Zentachain team will hold and stake at least 51% of the total amount of Zentachain. Therefore, we will not be exposed to this attack. With a PoS, the attacker needs to obtain 51% of the cryptocurrency to carry out a 51% attack. The proof of stake avoids this failure by making it disadvantageous for a miner with a 51% stake in a cryptocurrency to attack the network. Although it would be difficult and expensive to accumulate 51% of Zentachain, a miner with 51% stake in the coin would not have it in his best interest to attack a network which he holds a majority share. If the value of the cryptocurrency falls, this means that the value of his holdings would also fall, and so the majority stake owner would be more incentivized to maintain a secure network.