This weakness can become your strength with practice...Libra's nature is often easy-going and calm, as a result of their Venus ruler. They extend love toward everyone they meet, until someone shows they can't be trusted.
You just believe that people are basically good, and only hurt others when they're acting out of their lower nature. Others may sometimes mistake your easy-going nature as something they can walk over, or can even take advantage of your kindness.
But you never want to test a truly loyal person like a Libra. You can just as easily turn a cold shoulder to someone like this, and withdraw your affections forever.