How does someone know what you stand for, what you value, what your life’s work represents?
What are your values? What do you feel so passionate about you can't keep it in? What would you work tirelessly for? What makes you different from someone else?
All of the above defines your brand.
Don’t put the cart before the horse. The brand does not define you; in fact, YOU define the brand. People relate to brands just like they’d relate to people: they decide if they want to be associated with what the brand represents, if they want to be friends with it. The whole point is that branding emulates the way people think and feel and make decisions, not the other way around.
The reason you have a negative association with the word “brand” is because of the age of advertising when companies used the psychology of branding to sell you things you didn’t really need. That’s not what branding is about, that’s what cold hearted sales is about.
Hope you can see the difference. Building a personal brand is a way of taking ownership of the way people perceive you, and using it to create a mutually beneficial exchange of fulfilled needs.