I would like to recommend Hedyeh's place, because she is amazing host, the flat is great, big, with nice atmosphere and details, and I had amazing vacations with my family in Sevilla.
The place is like 10 min walk from the historical part and 20 min from train station. The beds and covers are warm and I slept like an angel. The place is super quiet!!! I will keep Hedyeh's details for another time in Sevilla. Cheers!