Here what is the meaning of grand ?

Ciara looks doubtful. “I thought you weren’t feeling—”

“I’ll be fine,” he says, cutting her off and then regretting it. He picks up the paracetamol tablets she’s set on the counter for him. “After these, I’ll be grand.”

They look the menu up online and then Oliver calls them to place the order. When they ask for a telephone number he gives them his own but with the last two digits transposed, as per his habit; he doesn’t provide any personal information unless it’s strictly necessary.