I think Brooke is the one who tried so hard to put a smile on her face and pretend like she wasn't broken on the inside. She struggled with the feeling of, in her own words, being "not good enough, not smart enough, not pretty enough" and we all know she has had many insecurities throughout the years.

In season one when she wanted her dad to be at home more often instead of working on the boat for long periods of time.Brooke also really fits this quote.

Brooke .. no doubt ..

Totally,Brooke.

My first instinct was to pick Peyton but then i realized she always had the strength to lie and say everything is okay.

This was hard.... Haley and Nathan have been through so much and with the icon of him in season 4 at the hospital he broke down and cried... so that was a low point and he wasnt lying....

And in season 7 when Haley's mama died, she was close to losing her mind... literally.

And Peyton has always had the most tragic things happen to her with psycho derek and then her real brother.. but she always tried to be fine even if she wasnt...

And Lucas in Season 6 when his mama and Peyton were in trouble.. he definitely did not hide his emotions.. he showed what he felt and you felt it too just watching it...

But Brooke.... she lost her company and her mama was a bitch her whole life.... she found out she cannot reproduce and she almost lost her life in that accident... she is not okay.

haley- season 2
brooke- season 3
peyton-season 1
lucas-sesason 1
nathan-season 2

Absolutely peyton. How many times has she put on a brave face and pretended like nothing happened. Most clear example IMO is Lucas & Lindsey's wedding.