1st
Imagine your best friend telling you they will always be there for you, but then they consistently cancel plans and don't make an effort to stay in touch. Their actions are showing you that their words are not sincere.
2nd
Imagine your boss saying that they value your hard work and contributions to the company, but then they deny you a deserved promotion or raise. Their actions are demonstrating that their words are hollow and not backed up by their actions.