The goal of any instructor is to motivate the student to stay focused.   All the while, feeling secured that what they are learning is being processed, thereby, increasing their motivation to stay the course, so to speak. 

Give positive feedback during class discussions.  This allows the student to feel confident that he/she is succeeding in the class.  

I have always believed that any problem can be resolved if we do not waste our time on the problem, but seek a solution.  Dealing with peoples emotions is difficult because we most likely do not take the time to understand and or deal with personal feelings that may be creating a barrier that leads to the solution.