Her hair is the same pink as all of the other ponies with fading pink hair so you do want to aim for that bright pink.
Personally the bright pink always sits a little uncomfortable for me but that's not because its not true to an original shade its just I am so used to a faded pink
![Smile :)](https://mlparena.com/Smileys/default/smile_001.gif)
When I rehair rather than repink I always fade the hair out a little before rehairing the pony. Repinking is a little different as it does not reach the bright pink of a rehair so you are already at a more comfortable pink shade. Just aim for the same colour you would when repinking a Posey/Lickety Split etc. Oh and with so softs be careful because depending on what you are using to repink, the flocking itself will take the dye colour too.