Knowing something so deep within is connection to your inner being or inner spirit.
Where does this knowing come from? Once you really begin to understand that you are two parts, you are flesh and bone but the most important part of you is this unseen energy of which you can feel.
How do you get to feel this unseen energy? This unseen energy is felt by way of your emotions, the better you feel the greater the connection, the less you feel the less is the connection.
This unseen energy delivers more emotional feelings to the good feeling thoughts and to the momentum you are creating to those thoughts.
These are only words, the only way to know is to test your emotions and to make your own discovery in how you feel to your own emotions, and to what comes next for you.
When you understand how your emotions feel, you are then able to make better choices to your thoughts and to which direction you want to create a momentum too or not too.
Have fun in this process and watch what happens when you do.