Hermina is a very friendly host and always responds to questions and concerns! Dorchester might not be the most beautiful area of Boston, but I was perfectly fine and didn't feel unsafe whatsoever. The house is beautiful and the code system for the front door makes things very easy. The rooms are small but pretty, the attic room under the roof is bigger, but not as beautiful as the smaller ones. Maybe that room is more appropriate for 2 or 3 students and not so much for a professional person.
Also: Follow Herminas directions from the airport to the house, they are extremely helpful!