Dortmund is basically safe. However, I would avoid deserted streets after dark. I would also avoid large groups of men. If you're not obviously carrying expensive items, there's little risk of being robbed. Public transportation is very safe.

Not safe overall, especially in the city. Thats where I live. There are many drunks and agressive football fans around everywhere, its a catastrophe. People arent friendly either and our neighbours were drug dealers, its a pain.

Dortmund is fairly safe, however in the city center and around the main train station you can find sketchy people and the number of homeless people and drug addicts is constantly rising. At night I prefer not walking but take rental scooters, my bike or public transport to get home.