It is the assumption that there will be sufficient beneficial random mutations to drive the process. There is no definitive way of proving that every beneficial mutation was caused by a chance event, so it all boils down to personal belief as to whether the mutations which brought you into existence were the product of random events or divine guidance.
Nope: as regards evolution there are your personal misguided beliefs and then there is the reality of evolution and these are not the same thing, where the TofE provides the best current explanation, and where this explanation requires no 'divine guidance': your personal opinion is, therefore, plain wrong.
The fundamental problem you have is that you start by simplistically presuming 'God', which isn't even meaningfully defined never mind being meaningfully evidenced, and in doing so you then resort to denying established naturalistic explanations in favour of your favourite fallacies: in your case arguments from personal incredulity and ignorance.