How can we get up employee's mental satisfaction about their service?

Appreciation is the most imortant word in this answer. The employee should always feel that the employer trust him/her. This mental satisfccation will be reached through steps, the first of which is good training, second is trus on the employee and last one is appreciation.

First thing is to not to treat them as employees. They are contributing to success of your company. Second is to treat them as humans. There has to be appreciation for their achievements. Salary has to be regular and just.