約束を守るべき

should keep promises

→ 約束
phrase Rare #37,854
should keep promises Expresses a strong expectation or obligation to keep promises. The ending べき means “should” or “ought to.”
JA: 友達との約束を守るべきです。
EN: You should keep your promise to your friend.

われわれは約束を守るべきである

We should keep our promises.

たとえ忙しくてもあなたは約束を守るべきである

Even if you're busy, you should keep your promises.

我々はいつも約束を守るべき

We should always keep our promises.

君は約束を守るべきだと彼女は続けていった

She went on to say that you should keep your promises.