There was a long pause, as Cecilia contemplated on if he should tell Robin when there was an evil woman in his life.
However, she also knew that Robin was wise, beginning from when he gave the villa to Sabrina instead of Zayla, though he claimed to hate Sabrina.
Even in hate, if he could keep his sense of reasoning, even after believing that the wrong person saved his life, then the old woman could conclude that he was indeed wise.
Also, the company has been flourishing well, which means that Robin had not allowed Zayla into its management.
That was another show of wisdom, keeping women away from the business. After having a firm hold on this analysis, Cecilia concluded that it was right to let him know, saying truthfully,
"Grandson, your father told me before he died that there was a treasure in the villa but I don't know what it is."