She's not ready. I would back off and let it happen in HER time. If she's crying and throwing fits, she obviously does NOT want to do it. I know it is not fun to keep buying diapers, but she doesn't sound ready to me.
Read her potty books that focus on positivity (the one my son and I loved was A Potty For Me by Karen Katz. It's very positive and makes it ok not to go, and celebrates when they do. The child in the book is also very gender neutral, so it can be a boy or a girl. Then just praise when she does go. continue to watch her and offer, but if she doesn't, don't despair. Also, don't ridicule. A few people in our family would say things like, "Aren't diapers for babies?" to my son, and I quickly put an end to that. Diapers are for whoever needs them. **ETA I just read some other responses, and noticed a lady trying to sell The Potty Train. This is a Discovery Toys book and it is very cute and very positive. Though I don't believe in offering to sell instead of giving advice, it might be one more tool in your arsenal!
My son potty learned at 3. We took our time, had many a naked day at home, I used training pants (undies that were easy to put on and take off for him, with a bit of absorbency in the crotch to keep the carpet dry while still allowing him to feel wet), and just asked asked asked. The only time he wears diapers is overnight. I never used Pull Ups (we use cloth diapers here, so I used cloth training undies too), but I've heard they are little more than a diaper and not a good idea.
My son did not respond that well to his special undies. He thought they were neat, but he couldn't pull them up and down as well. That's when the training pants came in. He loved wearing the undies until it came time to pull them down to potty. Then he would tell me he wanted a diaper. I just waited and let it happen naturally. To me this is the best way. It may take a little longer, but there is no stress, no headaches for any involved. Now he has no issues with the potty, and has no accidents (though accidents are completely normal and to be expected).
A lot of people use rewards/bribes. This has not worked for any child I know personally, but it does work for some. For the ones in my family (smart, stubborn, independent little ones!) they just had to be emotionally ready to go. And it had to be on THEIR terms, not on ours (my sisters, best friends, and I).
All that said, I really do think you need to not push the issue. She may be 3, but for some that is just when potty learning begins! She is different than your other two. I would say if she is "difficult" to train, back off and let her learn at her pace.