In the rooms for couples, there are 13 rooms * 2 people per room = <<13*2=26>>26 people.
So in total, there are 26 people in couples' rooms + 14 people in single rooms = <<26+14=40>>40 people in the hotel.
As each person gets a bubble bath, Isabelle will need a total of 40 baths * 10ml of bubble bath per bath = <<40*10=400>>400ml of bubble bath.
#### 400