The link works for me here. But the short answer is no, there is no guarantee. If you make a comprehensive, high-quality course in a topic that has high demand and little competition, you will probably attract a lot of students. But if you create a cursory, mediocre-quality course in a topic that has low demand and high competition, you're unlikely to find much of a following. It's really up to you to create content that resonates with Udemy's students. All Udemy does is offer it to them; they can't make them enroll in it.
The link Abbie sent talks about marketing techniques you can use to try and drive more people to your course on your own.
