Most things that go to trial are because there is a factual dispute. When the state presents a charge against you, it is up to the state to prove the case beyond a reasonable doubt. That is a high burden for the state to meet. You do not have to prove your innocence.
With that said, testimony is evidence. That evidence can be enough to convict a person. A jury is responsible for weighing the evidence to determine if that burden is met by the evidence presented.
If you have been charged with a crime, you should contact a criminal defense attorney to talk about your options.
Nothing in this communication should be considered legal advice. Nor should this communication lead you to believe that an attorney-client relationship has been created. Only after thorough analysis of your case with you in my office can I provide effective legal advice on your specific issue.