Understanding is always being aware that your knowledge is incomplete.
Learning, knowing, and understanding are the three steps on people’s intellectual journey through life. Not everyone reaches all levels.
Learning
Everyone has the ability to learn. Their interests will determine if they move onto the knowing stage about any subject.
Knowing
Knowing is the ability to retain and recall the information you learn. This is as far as most people will reach because they’re interested, but not that interested in the subject. A good example of this is people who know how to do their job, but may not fully understand how their job fits into business’s objectives.

Understanding
Many people acquire knowledge and retain it, but not everyone achieves understanding. Traits such as curiosity, critical thinking, open-mindedness, and a willingness to challenge one’s own assumptions play crucial roles in reaching this level.
You see, understanding requires effort and reflection, and not everyone is inclined or able to invest their time in this process.
Conclusion
The people who reach the knowing level without questioning if there’s anything left to learn are the luckiest people because they’re concentrating on enjoying their life, not trying to understand their life.