Brenda has revealed the couple - who are currently celebrating their first wedding anniversary - still act as though they're on their honeymoon, reported Washington Post.
"Kim and Kanye are still honeymooning in their minds. I think their marriage will last forever," she said.
Brenda - who is married to Kanye's father Ray West - claims she thought Kim was the "perfect" woman for him from the moment she found out they were dating.
"When I first found out they were going out, I thought, 'Finally, that's the perfect person for him'. Kanye is an alpha male, but I think he likes that Kim is a strong person and can hold her own," she added.