For someone who is honest and follows good moral standards, use the adjective ethical.

Is ethics a noun or adjective?

noun. (used with a singular or plural verb) a system of moral principles: the ethics of a culture. (used with a plural verb) the rules of conduct recognized in respect to a particular class of human actions or a particular group, culture, etc.: medical ethics; Christian ethics.

What is the adjective form of ethic?

ethic. Moral, relating to morals.