"Soy soltero porque nací de esa manera."

Simplified Meaning:

The person is saying that they are single because that's just who they are. It's like how some people are left-handed or have brown eyes; being single is just a natural part of them. Imagine a bird that prefers to fly alone rather than with a flock; it's not trying to avoid other birds, it just feels more comfortable alone. This statement suggests that being single feels right and natural to them, rather than it being something they are unhappy about or want to change. They're happy with their own company and don’t feel the need to have a partner to feel complete. This idea encourages others to accept and respect their natural inclinations, instead of feeling pressured by society to fit into a certain mold like being in a relationship.