"There is no evidence for life elsewhere in the universe."

"So you believe we're alone in the universe?"

After doing a lot of research into homeopathy we are now very confident that it does not work and cannot work.

It is also often a very bold claim to say "There is *no* evidence for X." The cases where you can truly say that are rare compared to how easily people (esp. non-experts) will say it. More often, it's more accurate to say, "I don't believe the arguments for X or evidence of X."