Hi,
I want to ask how to use 'concern'. When 'concern' means worry, it means to cause anxiety to someone. For example,
The state of my father's health concerns us greatly.
[+ that] It concerns me that he hasn't been in contact
So, is the following sentence correct?
You should not concern about how others think of you. No.
Say You should not concern yourself about how others think of you
or You should not be concerned about how others think of you.
The latter is probably more commonly said.
Best wishes, Clive