Sara Lance - Legends of Tomorrow
Being one of the two ladies on the Waverider over the past two seasons, Sara has really had to fight over the men in her life (as usual) to fight for what she believes in and what she thinks the team should do. However, it shows how strong Sara and her team believe she is, as she became the Captain of the Waverider, even after Rip's return. And she managed to do a far better job than he ever could.
Lucy Preston - Timeless
Lucy, being the only historian and woman on her team, is often having to stand her ground with Rufus and Wyatt to tell them what to do, what is right, and how things are supposed to work. Even with the stress of saving the day, and saving her sister, Lucy works tirelessly to protect history and she knows how much she means to the team.
Laurel Lance - Arrow
Laurel dealt with Oliver talking down to her for years, but she never gave up. She stood her ground when she took on the Black Canary mantle, even though Roy, Oliver, and Diggle were speaking to her as if she had no idea what she was getting herself into. She stood her ground when Oliver returned back and assumed everything would go back to how it was before, with him calling all the shots and being in charge of what Laurel does. Even in death, Laurel still knew what she wanted and who she wanted to be, and that's admirable on its own.
Mona Vanderwaal - Pretty Little Liars
Mona is an example of how to badly handle this belief. She took her aggression out on the girls, but she knew what she wanted, and knew how to get there. Even now, after months in Charlotte's dollhouse, Mona still knows that she's smarter than everyone else in Rosewood, and she has a bright future in front of her.
Lexa - The 100
Lexa was put into a position of power before she ever had a chance to learn to doubt herself. She knew that her word was law, so she had to start putting extra consideration into what she demanded, what she believed, and what she did, because all of her people were watching the Commander.
Olivia Pope - Scandal
Olivia isn't a piece to be won. She's the best at "handling" things, and she knows how well she does at her job. Her personal life on the other hand is quite messy, but no one is perfect. Especially not Olivia. But she has a blind determination to achieve her goals, and she won't let anyone stand in her way.