No, I don't think he'll forgive her if he found out at this point, but he would give her a chance to redeem herself though silently. I think he should be in the stage wherein he's beginning to enjoy her company. He sweetie not to fall in love with her, but you and I know that he will eventually. There should be something that will make him realize how he's fallen for her. Hmmmm...

Maybe the professor will have his little investigation on who Nick really is, because he suspects Nick to be the same person he met on the night before Nick and Claire were wed. Or maybe one of his associates will do that. Can we introduce a side character at the ball? The associate and middleman. He can be the third party who'll get between Claire and Nick, the threat that will make Nick realize he doesn't want to lose her. 

Tell me what you think.