Job satisfaction and turnover are connected because the way people feel about their jobs is one of the main reasons they might decide to quit. It's also generally true that people who like their jobs tend to perform well, and if an employee is performing well, a manager is less likely to have any reason to fire the person, which means involuntary turnover is also reduced. There are plenty of situations where job satisfaction and turnover don't really have any relation, but there is generally enough connection to make satisfaction a significant concern when managers are trying to reduce turnover rates.
There are a lot of reasons why people sometimes feel dissatisfaction with their jobs. Sometimes they don't like their bosses, or they may not feel like they are really suited to the work. In other cases, people may dislike their jobs because they don't have any friends among their coworkers or because their hours are difficult to maintain. These types of situations and feelings often connect job satisfaction and turnover.
When a manager needs to reduce turnover, he might look for ways to increase job satisfaction as one of his first steps. Some ways of doing this are fairly obvious, including things like increasing pay, giving employees better benefits, or making their hours more comfortable. It's also possible to increase job satisfaction by making better choices in hiring so that the people chosen are better suited to their roles and controlling employees who disrupt the workplace with overt hostility or unnecessary rudeness.
In many situations, there is no connection between job satisfaction and turnover, and sometimes there isn't very much a manager can do to keep certain employees. For example, if someone gets a job offer with better pay from another company, that person may choose to leave, regardless of his feelings about his current job. It is possible that certain incentives could be put in place to keep people from being recruited by other companies, but that doesn't always work out. There are also people who leave a job for reasons that managers have no control over, including personal issues, and when this happens, there is often nothing that can make people change their minds and decide to stay. In fact, they might really love their jobs and hate to leave, but life situations can sometimes compel them to leave anyway.