Locke tells her that Jack diagnosed a four-week period of healing, but Rose says "you and I both know it's not going to take that long". This is in reference to the airport flashback, revealing that Rose knows Locke was in a wheelchair before the plane crash.
Locke informs her that Jack predicted a four-week recovery period, but Rose responds, "you and I both know it won't take that long". This is in reference to the airport flashback, which shows that Rose is aware Locke was confined to a wheelchair prior to the plane crash.