Difference between to explain and to understand in Korean
설명하다·납득하다

설명하다to explain
To explain means to tell someone clearly so they can understand something. You use it when you talk about how something works, what happened, or what to do. In Korean, 설명하다 means to explain or give information in a clear way.

납득하다to understand
납득하다 means to understand something and feel that it makes sense. You use it when you hear a reason or explanation and accept it. It is common for rules, decisions, prices, and other situations where you say, “Okay, I understand now.”
The difference
설명하다 is what the other person does when they give reasons or details. 납득하다 is your reaction when you hear it and accept it.