Hard work alone will not bring you success. It is more appropriate to say that hard work is one of the keys to success. In fact even if you are able to accumulate all the keys to success, it is still no 100% guarantee of success. But if you determine and dedicate yourself to make hard work as one of the keys to success, you might have already increased the rate of success a lot.
Remember that most entrepreneurs fail a lot before striking the zone of success. That means you need to work hard enough to get through multiple failure before reaching your final destination of success. When you work hard, you are basically taking more shots or chances that others. Thus you will reach success sooner when you work hard.
By the way, the definition of hard work does not mean doing the same process again and again. Hard work basically means putting a lot of effort. The areas of effort that you need to put in are wide. Some of the areas include knowledge, experience and people skill. You need to be able to learn fast and apply the knowledge or skill instantly.
Without hard work, your success rate will reduce a lot. That is why we often say that hard work is one of the most important factors to success.