Trust- We all want to trust the people we love. Love sometimes blinds us to the reality of some situations. We think if we love someone we should trust them. But trust and love are two very different things. You can not particularly like someone but trust them because they follow through. You can also love someone but don't trust them. Many people might think that loving someone but not trusting them is horrible, but if you understand addiction you will see that it is not only a good idea but necessary for the family members emotional survival.
Addiction is a medical condition that neither the addicted person nor the family member can "cure". The addicted person can learn to manage their condition and live a healthy and happy life. In order to do this the addicted person must take responsibility for their condition, their past behavior, their present behavior, learn strategies to deal with uncomfortable feelings without using, and maintain a support system of other people in recovery.
Loved ones can be supportive but they must allow the addicted person to work their program of recovery on their own terms. Family and friends of addicted people usually have their own issues that need to be worked on but these issues generally get neglected because they want to focus on the addicted persons issues, family members may even mistake the addicted persons issues for their own.
It is important for family members to understand that the addicted persons issues are not your issues. Of course they effect you but they aren't yours.
Trusting your loved one will not help them in recovery. Allowing them to earn your trust will. So observe behavior, see if it matches up with the addicted persons talk, observe if there is follow through. Over time the person you love may even become trustworthy, but they don't deserve it until they earn it.