Give it up Mr. Yukon, sleepy jack is right. In fact, nothing is 100% certain. Even if they do find life, you can't know for sure that they're not lying or even that your life is not actually just a dream.
However, I agree that it is likely. Before, people thought that life was rare. Since then, beliefs have shifted and life is often more or less thought to pop up if it can. There's a lot of stochasticity, but even unlikely scenarios may become likely when repeated over potentially billions of years.