Translation:I am sure that I will find my keys somewhere.
A developer missed an opportunity. The definition of certa is both, certain and sure. Although the PIV is law, it's not for beginners. You have to already know the Esperanto word you are looking for, and be able to read the definition. But for those who don't know or can't read it completely yet, or prefer a better dictionary Tujavortaro.net is a 12 language 2-way Esperanto dictionary. It is better than PIV online in every way, unless you only speak Esperanto.