Most women can pretty much get sex anytime they want to irrespective of their appearance.
So, one day you and Zelda were having a discussion about relationships and she inquired as to whether you were currently involved?
You told her that you were very single, which made her then ask, "do you have friends with benefits?" Before you asked Zelda about her relationship status you told her that you feel like you're being interviewed for a job.
Zelda said, "In a way." She explained that she could go to almost any bar in the city tonight wearing a low cut blouse and act loose and there's a good chance that some guy will want to take her home with him.
However, I feel comfortable with you and it's convenient for me since we live in the same building, and it could be "No strings, just sex."
"We'd be friends with benefits."