The area around the Munich central station is safe. IMHO the main problem is that the area around the central station is a large construction site due to the rebuilding of the central station together with the works on the new suburban train tunnel.

A new addition to Marriott in Munich is the Königshof Exclusive Luxury Hotel in the Heart of Munich | Koenigshof Munich

An alternative would be the Westin or FourPoints (fromer Sheraton) in Arabellapark. The U4 subway stops there and goes directly to the central station (takes 11 minutes) and downtown Munich.