That day she could not have been lovelier, and we had a wide-ranging conversation.
You were certain that she was smarter than you, lovelier than you, more interesting than you.
Old English luflic "affectionate, loveable;" see love (n.) + -ly (1). The modern sense of "lovable on account of beauty, attractive" is from c.1300, "applied indiscriminately to all pleasing material objects, from a piece of plum-cake to a Gothic cathedral" [George P. Marsh, "The Origin and History of the English Language," 1862].
An attractive woman: where flabby lovelies in polka-dot bikinis lobbed beachballs around (1940s+)