The main character of the book was selected to travel space with these aliens that also were able to act as spaceships called the Leviathan. They were helpful to Earth in fixing its problems.
As they travel across space, the main character encounters another species traveling with the Leviathan. She realizes that they help many different planets, not just Earth. The other alien asks her to identify a bond name or something like that, but she doesn’t understand what that is.
Later on in the story, she becomes closer to the Leviathan she travels with, and they identify as a combination of their two names. I have tried searching for books called Leviathan, but cannot find the one I am looking for. It is a standalone novel.