The phrase "whatever happens, happens" expresses acceptance of whatever happens in the future. It is a mindset of going with the flow and accepting where the situation takes you. This phrase suggests that the outcome in the future is uncertain or out of ones control, and it is a way of handling situations, good or bad. It means that you don't have control over whatever is going to happen, and you're not going to do anything. The phrase can also be interpreted as a way of accepting that whatever happened in the past or is happening now is happening for the good.