Answer: Bullying is repeated insults or repeated physical offenses and when someone is repeatedly insulted they start to believe that there is something wrong with them. This psychological effect forces the idea of them being bad people into their brain even though it is not true. This leads to the victim believing they are less than others. This makes them feel unwanted and can lead to low self esteem and even suicidal thoughts. So victims have low self esteem because they are repeatedly insulted and degraded which lowers their self esteem.
Hope this helps