First, let's get caught up on the drama. Eilis, who married Tony before returning to Ireland and getting embroiled in an affair with Jim Farrell, who doesn't know that she's married. Jim asks her to get engaged and she considers staying, but is forced to return to BKLYN after Miss Kelly alludes to knowing about her Italian-American hubby.
In other words, it's a huge mess.
In fact, there's only one thing we know for certain: Eilis is returning to Brooklyn. We don't know if she's returning to her husband, as she told us earlier that "she was sure that she did not love Tony now" (4.226). We don't know if she's going to give things a shot with Jim, whom she promises to explain things to when she returns to Brooklyn. To be honest, however, Eilis might ditch both of these guys.
Despite her hand being forced, Eilis now realizes that the only place where she'll have the freedom to make choices is Brooklyn. She might not have all of the answers right now—she might even be fuzzy about the questions—but she knows she'll have to return to the big city to find them.