I really must go
I truly have to depart. Used especially when one's intention to leave has already been stated. Thank you for the drink, but I really must go now. I'd love to stay longer, but I really must go now.
(I) really must go.
an expression announcing or repeating one's intention to depart. Bob: It's getting late. I really must go. Jane: Good night, then. See you tomorrow. Sally: I really must go. John: Do you really have to? It's early yet.