Most people would be upset if they found out that their dental bill was a lot more than they had anticipated and so someone being pleased about it is definitely sarcastic.
Context: "I was furious to hear that my dental bill was three times of what I was expecting!"
Hypothesis: I was so pleased when I found out that my dental bill was triple the amount I thought it would be!
Based on the context, is the hypothesis true, false, or unknown?