closeness tends to get handwaved as a "she's my teammate/a fellow rogue" thing, or "she's saved my life more than once" (which both of us have done for the other).
Nod, and that works well for a lot of campaigns where the focus is on the adventure, not role playing and character development. As in, the setting isn't fused about the issue, and the actual players don't care much about what the characters do outside of the dungeon.
Kinda reminds me of a buddy cop action movie -- there might be a hint of something more than just buddies (especially in the scriptwriter is having fun messing with the genre), but for the most part, the audience doesn't care if the innuendo is true or not.