What concept provided in amendments 5 and 14 guarantees that the gov will treat you fairly and use fair and reasonable written rules and procedures before your life liberty or property are taken?

This is called the Due Process of the law. It means that all the laws should be observed and followed to their force before action is taken, and it was put into place to keep officials, elected or otherwise, from abusing their power and taking things and punishing people on whims.