The word that best fits the blank is expect.

The sentence means that no one should think or believe that they will become rich without hard work. The word expect means to think or believe that something will happen. In this case, it means to think or believe that you will become rich without hard work.

The other words do not fit the blank as well.

• Accept means to agree to something or to receive something willingly.
• Except means to exclude or to leave out something.
• Excerpt means a part of a written work that is taken out and used separately.