Sometimes the hardest thing to do after being betrayed is learning to trust again. For some it does not come easy when they end up extremely adhering to "Love all...but trust one" which can lead to them being bitter and distant to even trustworthy people.
However, everything has got its balance. I think distrust in moderation is a good tactic that can shield us from getting hurt when used well. Nevertheless, there are times we need to learn to trust others again or gain their trust.
Last but not least, know the difference between when it time to move on and throw out the "trash" after betrayal; and when it is actually time to recycle that "trash".