Weak girl transforms into brave girl through the episodes?

The female lead is weak and innocent and very naive at the beginning..  she doesnt talk back to others , trusts easily.. she is not a kickass female lead at 1st..

Then because of hardships or schemes of villains or any other reason she transforms into a strong brave girl & gives back to ppl who hurt her..

Any dramas like that?

I mean some dramas start off having a brave female having a sad past.. but instead of already seeing her as a strong character in 1st episode,  i want to watch the girl's character  grow through the episodes.. Hence any drama where a poor, innocent girl transforms into a brave girl through the episodes?

Ishi no Mayu- FL becomes a cop because of her dad. Hella weak and annoying but she becomes stronger as we progress. There is a second season but I havent seen it yet.

Fated To Love You

Oh My Ghostess

Although this drama doesn’t necessarily deal with revenge (which is what I assumed you were somewhat looking for from reading your description), you see the female lead grow immensely from a shy and timid girl to someone who can express her feelings openly. The second lead female also changes as well with the help from the first female lead and vice versa.

Be Strong Geum Soon

Birth of a beauty

nice witch

twenty again

birth of a beauty