Sandro Assistant Store Manager interview questions

Had a 1to 1 interview in store at Brompton Rd 303, London SW3 2DY London with two managers. A very friendly atmosphere during the interview process .The interview last 30 mins. The manager was positive to hire and even advise not to accept other offers from interviews. Finally, didn't keep her promise to let me know the outcome the next day. She just emailed me 4 days later to reject my candidature. Did not give a real reason why she didn't want to hire me.