WMG / Star Trek: Voyager S7E23 "Endgame"

Miral Paris lost a younger brother in the Delta Quadrant

...and this us why she was willing to let Admiral Janeway alter her entire life. There are hints of tensions on the Paris-Torres family, and B'Elanna is very concerned about her daughter's secret mission. B'Elanna doesn't want to lose her remaining child. Tom and B'Elanna had a second child in that timeline, who died young during Voyager's long and dangerous journey home. Miral blamed herself for her little brother's death, and never got over it. She may not have known the details of Admiral Janeway's plan, but she surely knew there was a time travel device involved. Undoing her brother's death may have been part of the deal between Miral and the Admiral.