Reports of their marriage came after the couple this week began their tenth year together after meeting as students at St Andrews University in Scotland.
"She can hardly believe that all those years have slipped by and she's still uncertain about the future," the Daily Star quoted one friend as saying. Kate does not want to be still waiting around on their tenth anniversary next Oct.
"It's a clichi but she really has dedicated the best years of her life to William. Most of her friends are married and starting their families. Kate loves William but the longer this goes on, the stranger he seems to her."
William's aides say the prince already thinks of himself as 'privately engaged'.
"His view is that he's protecting her from the pressure his mother Princess Diana suffered in the public eye." said one friend close to William