How do you ask: Would you like to go out to dinner with me tonight?

Question

Answer

今晩　お食事をご一緒願えますか？
　
晩飯一緒にどお？

Answer

Formal ;
あの、もしよろしければ、今晩、御食事を一緒にどうですか（しませんか）？
Ano, moshi yoroshikereba, konban, oshokuji wo isshoni doudesuka (shimasenka) ?
When u use ask someone out, u should say this with checking the someone's face with feeling. that would be best. :)

With friends ;
夕飯、食べ（に）行かない？
yu-han, tabe(ni) ikanai ?
飯、行こ～！！！
meshi, iko~!!!  ^^/

Answer

今日、一緒に外で夕食をしましょうか？