Marie Claire magazine says the actress's 'face crumbles' and she 'starts to cry' particularly when discussing her feelings for her daughter Matilda for losing her dad.
"Very obviously, for me and for her, there's a hole in our life," Michelle told the US magazine.
"The natural inclination is to want to fill it and make it disappear, but what I've come to recently is that it's impossible.
"Nothing will fit in that hole because what we want back we can't get, which is this one person.
"I'm trying to be respectful of the absence. I'm not trying to fill it up. It's what it is."
Saying that "everyone has a tragedy, I met mine a little early", Williams - who also insists she is not dating Ryan Gosling - gets most upset when talking about her daughter.
Her tears started rolling when she recalled a touching letter sent to her by a stranger who had lost his wife - attached with a beautiful photograph of their smiling daughter.
After pausing for tears, Michelle finally explained: "It made it possible for me to feel that my daughter could smile like that, after what she's been through. That letter gave me hope."