Hi everyone. It's wonderful that you help each other through the learning process and that you inject such positive energy to this forum!
Regarding the original question, Aurora, I believe the English script is what's causing the confusion. The "sí" included in the Spanish phrase is a means to reaffirm something. Eg: "no escuché hablar de Diego Maradona, pero sí escuché de Lionel Messi" / "I didn't hear talks about Diego Maradona, but I did hear about Lionel Messi". This is one of the cases in which a literal translation is difficult; "but yes I heard..." doesn't sound right, does it?
Would it be clearer if the English phrase was changed to:
"But you <do> hear about a high interest rate."?
I look forward to your comments!