YOU SAID:

i want to eat dinner but i cant be bothered to go downstairs

INTO JAPANESE

夕食を食べたいが、階下に行くことができません。

BACK INTO ENGLISH

You can't go to dinner but the downstairs.

INTO JAPANESE

夕食が階下に行くことができません。

BACK INTO ENGLISH

You can't go downstairs to dinner.

INTO JAPANESE

あなたは夕食に階下に行くことはできません。

BACK INTO ENGLISH

You cannot go downstairs for dinner.

INTO JAPANESE

あなたは夕食のため階下に行くことはできません。

BACK INTO ENGLISH

You cannot go downstairs for dinner.