Knowing a Partner's Character

One of the most challenging parts of a relationship is figuring out your partner's character. How do you tell whether the person is acting, lying, pretending? We recommend that the process starts with understanding just what character looks like. So, our books describe what qualities like loyalty, truthfulness, faithfulness, etc. look like. But, how can you take that information and check out whether his/her words are really matching with actions not only with you, but with everyone else too? Any ideas?