According to the rules on page 13, an unreliable ally becomes reliable at the end of a bound in which 4 more enemy than friendly elements are destroyed or become broken (I don't have the rules with me for the exact wording, but it's close to this).
Those 4 elements: must they be destroyed/whatevered in that particular bound? Or is it a cumulative thing?
So, for example, say I have an unreliable ally. In my bound I destroy 2 elements and lose nothing. In my opponent's bound I destroy 2 more elements and lose nothing. Have I done enough for my unreliable ally to become reliable?