Is it okay to scold a three-year-old in public? How do I do it so that it does not hurt her?

Rather than scolding her in public, try these methods to get her to behave instead. http://www.parenting.com/article/toddler-discipline-tricks-work If you have to chide her, squat down and look at her at eye level instead of looking down at her. Talk in a firm tone, but don't raise your voice. You may say something like this "Mummy feels hurt because you refused to leave the store when I asked you to". It gets her to empathise with you instead of feeling sulky about getting scolded.