The artist was speaking at the launch of “National Thank You Day”, a fundraising campaign in aid of the Irish Hospice Home Care Programme.
"No question, becoming a mum was the best thing that ever happened to me and the most rewarding aspect of my life," said the mother-of-four.
Sinead was accompanied by her youngest child, four-year-old Yeshua at the event.
National Thank You Day takes place Thurday in Ireland and is asking people to thank their family and friends with cards featuring messages by popular figures such as Gabriel Byrne and Seamus Heaney.
"I hope when I die I get to go to a hospice," Sinead said at the event.
"It's nice to create a place with a peaceful atmosphere, where maybe you can create some way of people enjoying the journey.
"We all have a very negative attitude towards death which I don't think is really accurate," she added.