From a borrowed, shuffled deck, have your spectator pick out her favorite card. Have her replace it in the deck and set the deck down.
With no funny moves, you pull out two cards to help you find the chosen card.
Within 5-10 minutes, the two red sixes indeed emerge triumphant having caught the selected card!!
Q: Does the trick really need 5-10 minutes?
A: It is highly recommended that you give the sixes time to do the job right.