Catherine, Princess of Wales' siblings Pippa and James Middleton understand that rare feeling.

“I remember putting him through his paces when we first met,” James wrote.

“Did he deserve my sister?

James Middleton smiling and walking with Prince William

He had to earn my trust.

Likewise, in his memoir, he wrote about admiringPrince William and Kate Middleton’s relationshipfrom afar.

“William was a fantastic support for us as a family,” James confirmed.

James Middleton smiling on the red carpet & Prince William smiling in a tuxedo

For more Middleton family drama, check outthe awkward way James' wife Alizee Thevenet met William and Kate.