In one scene of Fences, They all laugh in this scene when Rose Maxon says these words:
Man, hush your mouth. You ain't say no such thing. Talkin' about, "Baby, you know you'll always be number one with me."
What is so funny in these words?
As I remember Troy was explaining how he conquered Rose. I don't remember the exact words they used in the scene, but was something in these lines:
Troy explaining what Rose and him said in the night they met:
Rose: What will be number one for you, baiseball or me?
Troy: You know it will baiseball, but if you work on it, you can get close.
Then Rose said the phrase you mention on your question, basically telling it was a lie, that Troy was crawling for her:
Baby, you know you'll always be number one with me.