Wilde did visit the USA and this quotation is certainly in keeping with his style. There's no evidence to prove conclusively that he said it though. His US tour was very successful and Wilde became quite famous there, so it is also possible that the 'quotation' was made up for him.

There are many quotations attributed to Wilde - "I can resist everything except temptation", "We are all in the gutter, but some of us are looking at the stars", etc. There's no particular reason not to accept these attributions, as he was clearly highly adept at coining the repeatable phrase. These are a few that can't be questioned, as they come from his published works:

"Life is much too important a thing ever to talk seriously about it."

"To love oneself is the beginning of a life-long romance."

"Women are meant to be loved, not to be understood."

Statue to Oscar Wilde in Merrion Square, Dublin (nicknamed 'the Quare in the Square').

See also - 'the floozie in the jacuzzi'.