Establishing the truth of something is the process of proving it to be true. This can be done through a variety of methods, such as gathering evidence, conducting experiments, or analyzing data. The term 'establish the truth of' is often used in legal contexts, where it is necessary to PROVE the truth of a statement or claim in order to reach a verdict. In this context, the term 'PROVE' is often used as a synonym for 'establish the truth of'.