I applied online and through a Marriott employee referral. The process took a little over two weeks.
Once you submit your application, a third party company reviews it and rates your assessment. If it doesn't meet criteria, you probably won't be contacted for an interview.
If your assessment passes, your application is sent to the hotel with an opening like mine was. A hiring manager will contact you by phone and ask you general questions about your background, education, what languages you speak, etc. Really, the phone screening tests whether or not you are a pleasant person with a good voice that sounds positive and clear on the phone.
If the manager thinks you sound good, they will schedule an in person interview. This interview was with the same manager and took about an hour. It was very relaxed yet professional. We talked about how the hotel ran and the training opportunities available for guest services. Yes, the starting pay is very low but if you can handle it, the company has many options for training and development! The interview itself was STAR questions as others have said (situation, task, action, result) and if the interview goes well you will be scheduled for a second interview. For guest services you need to have an outgoing personality and love working with people, and be open to learning new skills.
I was asked to meet with the assistant general manager the next day. We talked about my goals and where I saw myself in the company. It was laid back but still asked me about how serious I was about the position. At the end, I was offered the job and taken to the HR office to sign a consent for a background check and drug tested before I started work.