I totally can recommend Karstens Airbnb offer. Karsten is a friendly, helpful host at any time and the accommodation is safe, clean, comfy and quiet. I stayed there alone and felt pleasant every time.
Supermarkets are close. U have good access to public transport via the train to everywhere in the city or outside. I highly can recommend the walk on the harbourfront via the Little Mermaid and the Kastellet to the Inner City, it´s so beautiful and will take around 40 minutes (to Nyhavn for example).