Incredibly easy, they did not even ask me many questions, mostly talked at me and told me about the job. Some of the reviews here say they make you sell them something, I was fully prepared for that but they did not ask me this. They definitely want to hire bathers to become groomers, so if you have no interest in going into the grooming academy, do not even bother applying for this position, you will probably not make it to the second interview.
First interview is with the salon manager, she told me about the job, about being able to move up to grooming, etc. Then with the store manager, which is more of a formality. Make your impression good on both of them but especially the store manager. They have more say in whether you get hired.
Make them know your experience dealing with people AND animals as this has a lot to do with both. Let them know you are not going to be bothered with the working conditions and that YOU WANT TO BE A GROOMER, even if you don't, and you want to stay a bather, show interest in wanting to be a groomer. They will not fire you if you change your mind when you start the job.