Women in Sojourner Truth's time period were expected to be quiet, submissive, weak, dependent, and docile. As The Narrative of Sojourner Truth illustrates, Sojourner was none of those things, but instead she was outspoken, self-willed, strong, independent, and assertive.
For example, she openly and defiantly left her slave owner, Dumont, on the day he had promised to free her, despite his reneging on his promise to do so. She went to the home of Isaac Van Wagenen, who bought out her last year of service from Dumont. This was a bold gamble that could have gone badly for her, but Truth was a risk-taker.
Truth also boldly changed her named to Sojourner Truth (her birth name was Isabella Baumfree). She also became a preacher. Other women were preachers during this time period, but this was hardly a gender norm in her society. She took on male preachers outspokenly and insisted that her physical strength and suffering as a slave had prepared her to withstand any test from God that would prove her fit for his kingdom.
Truth also defied gender norms by wanting to achieve financial independence from her memoir rather than be dependent on a man, another goal she managed to achieve.