If you're still looking for a place to stay in Sevilla, STOP LOOKING! You've found the best place around.
Concepción's apartment was perfect in every single way. Not only was it extremely clean, safe, and exactly as it looked in the photos, but the location is truly unbeatable. Extremely close to the city center (approximately 3 minutes walking from the major shopping streets), across the street from a 24-hour taxi stand so it's easy to grab a ride anywhere you'd like to go, and surrounded by grocery stores and department stores so that you can easily pick up anything you may have forgotten to pack.
Concepción was also an incredible host - she was very flexible for check-in and check-out, provided us with very useful recommendations all around the city, and even went out of her way to help me when I was having passport difficulties before I even arrived in the country. All in all, Concepción and her apartment were definitely one of the highlights of our trip. Five stars all around!