Lyric discussion by Yellowheartballoons 

Cover art for What If? lyrics by Bombay Bicycle Club

To me this sounds like it's about someone who loves someone who's very shy. He's not sure if he really wants to be with her, because he has to make so many moves. But she's special to him so he tries, because I think his friends or something else gave him courage.

"And what if only one of us had the guts tonight.."

Something might happen, he wants something to happen. :)