。
She looked at me and smiled.
Literal
She [topic-は] me [object-を] saw [and-て] smiled.
微笑する uses the Sino-Japanese 微笑 (びしょう, 'smile') with する — a slightly more formal, written-feeling alternative to the native verb 微笑む (ほほえむ). Both mean 'to smile' (a gentle, modest smile, as opposed to 笑う 'to laugh / to smile broadly'), but 微笑する reads as bookish, fitting for narrative prose. The te-form 見て chains the seeing into the smiling — 'saw and then smiled.'