The library's location is up for debate, and Chicago is facing tough competition from New York. Right now, both the University of Chicago and University of Illinois at Chicago are trying to bring the library to the city.
"There's no question and what I was told was, when it comes down to where their heart is, the first family is committed to Chicago, but they got to put together a library and an undertaking that really is solid, so that no questions are asked in the future, about whether it was put together in the right way," Durbin said.
Two public hearings are scheduled for next week to deal with securing land in Chicago for the library.
U of C revealed its plans on Wednesday. UIC revealed its bid last month.