Did Gil really love Cecilia?

I tend to agree with you as well...I think Gil was doing whatever he felt necessary to get Baxter back onscreen and if that meant convincing Cecelia that he was in love with her then so be it. I think the look that the OP mentioned that Gil gives towards the direction of Cecelia is more guilt than love lost. I think he feels bad about some of the things he had to do but I never got the feeling that he really loved Cececila. Baxter did, Gil didn't.

I think Gil was protecting his career more than anything. Sure he found her charming but the bottom line was getting Tom Baxter back in the movie so he could pursue his career.And he "acted" like he was a competitor for Cecelia's affections, gave her reason to believe there was "chemistry" so Tom went back in the picture.
Then next day he "couldn't wait" to get back to Hollywood. I'm sure he did think of Cecilia on the plane though and wondered what if things were differnt....

It wasn't me who said it.. my film professor did!

Tom Baxter loved Cecilia because it was "written into his character," as he says. The script of the movie within the movie presumes he is the ideal, or "perfect", man, and whatever Cecilia desires in a man is reflected back to her. (Remember the scene in the brothel? There too, Tom has that function for the women around him.)

Gil Shepherd, however, is a real human being, and thus more complex - and he has some flaws. At first he responds to her flattery, flattery based on his movie roles, not the real person, because Celicia doesn't know him except through his films. He is more interested in her opinion of him than in what she is really like.

At the end, I think, he realizes that she could never fit into his life in Hollywood. He may have a guilty conscience about it but, as an actor, he is able to understand the diffence between reality and fantasy better than Cecilia can.

I think it's quite simple: Gil probably did fall in love with Cecilia, but this love didn't match the love he had for himself. He likely didn't believe he could continue his Hollywood career with Cecilia at his side, so he had to leave her behind -- although clearly it wasn't an easy decision.

I don't know what movie you were watching, but Gil didn't love Cecelia...he was doing and saying whatever he needed to do or say to get Tom to go back in the movie. If you think Gil loved Cecelia, I have to wonder if you saw the entire movie.

I doubt that he loved her at all. He certainly may have felt bad about deceiving her but he was more interested in making sure his acting career wasn't ruined.

He's taking the knife out of the Cheese!
Do you think he wants some cheese?

I think Gil loved the idea of Cecilia loving him. He loved the attention and admiration, but true love they are not. At the same token, Cecilia also loved the idea of this big celebrity star wisking her away from her dire domestic life. You see, there is "love" and there is "true love". True love is giving up everything that is important to you for that person, loving them despite their celebrity status, their flaws. The other side of love is the conditional love. Gil was "loving" Cecilia on the condition she would persuade Baxter to return, and Cecilia was "loving" Gil on the condition of him taking her to Hollywood. The only person who truly loved someone was Baxter loving Cecilia, hence he unconditionally gave up the real world and return to the celluloid screen for her. So the question is who did Cecilia really loved? We get to see her in the end, sad and alone, thinking that she was blinded by reality and the only thing that was truly real was the character Baxter.

Sometimes I wonder of Cecilia's state of mind. She strikes me as someone who is willing to go with any man just to get away from her husband. She was willing to go with Baxter but when the next best thing came along, she was willing to go with Gil. Cecilia is always waiting for something to happen in her life and when the best (Baxter) has happened to her she lost him to the "fake" person. What Woody is trying to convey is- Is love real? Is the love of Baxter, a movie character came to life, real or is the love of Gil, made of flesh and bones, real love? As we see, real true love was Baxter. And Cecilia was too gullible, naive and a bit greedy to realize that her actions resulted in the love she lost.

"my career is on the line" was his main focus and he loves all the attention he gets from Cecilia and others and is concerned about the next big thing in his career as an actor