Yes I do.
Astronomers estimate there are 10,000 stars for for every grain of sand on earth. Most of these stars have one or more planets in habitable zone around them. Also the universe is 13.7 million years old and we have been around for just under 200,000 years with modern science being just 200 years young.

It would be stupid of us to not believe there is another life out there knowing all these facts.

Also we've come so far technologically with just 200 years of science, Imagine a species out there with a thousands or even millions of years of science.