Bologna

Yes, for a solo weekend built around food: the centre is walkable, the Mercato delle Erbe food hall serves dinner until midnight and one hostel runs a free event every night. The catches are price, with dorms from 22 euros, and how safe people feel after dark: Numbeo users rate walking alone at night low.

Naples

It depends how much perceived risk bothers you. Naples is cheap, eating alone standing at a counter is normal and central hostels put on something every night. But Numbeo users score walking alone at night at 27.5 out of 100, the lowest of any city in this guide. It works if you stay central and head back early or in company.