people who are stong on the inside. 내면이 강한 사람.

have a strong person, inner part. not outside part.

people who are stong on the inside look like frendly and sweet on the outside.

they are not swayed by others. 

whatever influence the people around you have, you focus on your life and do not suffer from unnecessary stress.

they are also good at expressing their emotions.

when they're angry, they don't explode their emotions , and they shake them off wisely at the right time

building a fence in my mind indepenently so that toe initiative in life does not fall to other (인생의 주도권이 타인에게 넘어가지 않도록) can make a more confident life than anyone else