Prince William and Kate Middleton have been going strong since their April 29, 2011 wedding ceremony at Westminster Abbey in London, but it wasn't always smooth sailing. According to a new report, the Duke of Cambridge initially had some reservations when it came to contemplating proposing to Kate. What were they?

According to Express, Kate always believed that the Duke would propose to her at some point. An insider close to the couple revealed that "as far she she was concerned, it wasn't a question of 'if,' just 'when.'" However, at that time, Prince William reportedly wasn't ready to settle down with her because he believed "all the fun" was gone in their relationship. 

READ: Prince William, Kate Middleton Didn't Meet At University: Here's What 'Changed Everything'

Reportedly, as time progressed, so did the royal's view on a potential engagement. This was due to the fact that "the way in which the public was starting to view Kate as a future princess" was supposedly an important influence. Subsequently, a proposal would also mean that Kate would one day become Queen Consort, which also may have weighed on his mind.

Fortunately for the pair, they would go on to announce their engagement in 2010 and are now the parents to three children, Prince George, Princess Charlotte, and Prince Louis. As for what the pair are up to lately, they have a tour of Pakistan lined up later this year.