Hello @Scarlett_Clay! I am one of Ravi’s correspondence assistants, and I would love to help you out.
When I was doing my thesis research in a history program, I was often met with sources that quoted from older sources that were no longer in print and could not be verified. This can be very frustrating! It may very well be that Oscar Wilde asked Robbie Ross this question, but unfortunately I cannot locate the source for this exact conversation.
However, the historical record does show that Oscar asked this question of his friend, the notorious blackmailer Robert Cliburn, who had much in common with Robbie Ross (both were lovers of Wilde and younger men). You can find this conversation recounted in Neil McKenna’s book, The Secret Life of Oscar Wilde (Basic Books, 2006). McKenna’s source for this quote is the diary of George Cecil Ives. In an attempt to remain accurate to the currently available historical record, Ravi’s description of this question in his book Sense and Sensuality puts the conversation between Wilde and one of his “partners in crime,” and not between Wilde and Ross on Wilde’s deathbed.
I hope this helps!