what is difference between confidence and over confidence?

confidence            :  If i say i can get this job.
over confidence    :  If i say I only can get this job.
                       OR

confidence            :  I will be selected in this interview.
over confidence    :  surely i will select in this interview.
                       OR

confidence            :  I am the right person for this job.
over confidence    :  NO one else is better than me for this job.