You need to find the right balance between doing what you want to do or what excites you (metaphorically represented by the heart) and doing what you know you should do or have to do (metaphorically represented by the brain.)

The word brain is misspelled, but I guess it's a typo(a small mistake in a text made when it was typed or printed) and now the main issue It is a state of unity between your brain (mind) & heart (spirit). This state of harmony allows you to be more present and aware.

The brain and the heart together make a great team. It means, the brain does half of the job, and the heart does the other half of the job, in making decisions. Specifically, the brain thinks (conscious mind), and the heart feels (subconscious mind). When you consciously think something is right, and you also subconsciously feel something is right, then it's probably right - it's a safe decision.