Kim Kardashian West ''totally understood'' her brother Rob's decision not to attend her wedding.

The sock designer flew out of Paris, France the day before his sister tied the knot with Kanye West in Florence, Italy, in May, reportedly due to feeling increasingly unhappy with his weight gain, and while the 'Keeping Up with the Kardashians' star insisted they never fought about his decision, she admits he didn't tell her face-to-face that he was leaving.

Speaking on 'Watch What Happens Live', she said: ''He sent me a long email the morning of, that he was going to leave. There was no fight.

''I just thought, 'You know what, this is my day, I'm not even going to worry about it.'

''I totally understand that he wouldn't want to see a lot of people if he was feeling uncomfortable and you can only pray and wish that someone would not miss out on more memories in life, because life is about memories.''

While Kim - who has 13-month-old daughter North with Kanye - insisted she wasn't ''non-empathetic'' over Rob's problems, she admitted she gets ''frustrated'' at his apparent lack of effort to change things.

She added: ''My brother and I are so close, he's one of my best friends. I'm definitely a tough love kind of person. If I don't like something that's going on in my life, I change it, and I don't sit and complain about it for a year.

''I try to encourage him. And once you don't make that change for so long, and it's not happening, I get frustrated. My patience runs out.''