What's this quote mean?

Question

Witts can hurt someone who wears their heart on their sleeve.

Answer 1

It means that some one who is sensitive and doesn't have a thick skin can easily be hurt by mean remarks.

Answer 2

"Witts?"   Makes no sense to me

Answer 3

"Witts" is tin ore freed from earthy matter by stamping.

Perhaps you mean "wits."  If so, wit is typically a form of intellectual humor.  A wit is someone skilled in making clever remarks, typically in conversation and spontaneously.  However, to the very sensitive (i.e., "someone who wears their heart of their sleeve"), a remark that is witty or saterical, without regard to intent, can be heard as sarcastic or biting and, thus, hurtful.