Q: Will we see Oliver have a challenge in being truthful and honest with [Felicity], or is that part of their attraction, that he can’t be honest and truthful with her?
A: What’s fun about the season premiere is you do get to see him be honest and truthful with her. For both good and bad. I think he’s finally revealing some secrets that she didn’t know. And her reaction to those secrets is interesting.
I think they’re in love with each other, and when you’re in love with someone it’s very hard for that person you love to tell you something that’s going to make you fall out of love with them instantaneously. But that emotional intimacy deepens their relationship, deepens their connection."
— Marc Guggenheim on Oliver and Felicity in season 3 (x)
The fact that Marc Guggenheim said himself that Oliver came really really close to telling Felicity about his feelings in 2x06 with that “Because of the life that I lead…” speech.
…aka, Oliver Jonas Queen has been in love with Felicity Megan Smoak at least for a year. I repeat, for an entire year. PASS IT ON.