Actually putting her in underwear and taking the pull-ups away, is the best way to go, Both my Sons were potty trained at 2 1/2 years, I had made the mistake of buying the pull-ups for my oldest son, but it just postponed the process, Once I started putting them in the underwear, It made them realize that they were wet, and it was unconfortable, so normally they would be like "UH OH Potty" and run to the potty, Even if i was upset, I felt that putting them on the potty after an accident, was just showing them where they needed to go. Yes it can make a mess and it is alot of extra wash, But it moved the process along alot sooner, they started picking up on it on their own, I think it was only a Month or Two and they were completely Potty trained.
My Daughter is Going to be two in March and We just bought her, Her First New Undies, Probably like 12 to 16 pair but, I don't have an excuse to put her back into the diapers around the house, and if she has an accident the first place she runs is to the potty and she's already got there in time a couple times.
My Cheat is Shirt and Underwear, I don't put the pants on her. It easier for her to do it her self. That What she likes.
The Reward Stickers or a Sticker chart Worked too, I don't think you can over due the Good job and the cheering, they like to know you are proud of them, and that they made you very happy, cause they do want to please you.
They Normally like the Idea of BIG KID underwear. And if they get to pick it out that may give them more reason not to pee on the undies.
A three year old, that doesn't want a diaper because it pinched, I would defenetly take the Pull-ups away, Maybe buy a bag of diapers to go with the underwear, She will make her own decision. I think she'll go for the Underwear. Because the diapers are unconfortable, just like wet underwear.
And do the one thing most parents do not think of, Ask her if she will Please use the potty like a big Girl, and if she says No, ask why not. You may get something from her.