YOU SAID:
They might have found their welcome here less warm than they hoped, had you accompanied them; but it is no matter, for that was not their errand.
INTO JAPANESE
彼らはあなたが彼らに同行していた場合、彼らが望んでいたよりも暖かいよりも暖かいここで彼らの歓迎を見つけたかもしれません。しかし、それは彼らの用事ではなかったので、それは問題ではありません。
BACK INTO ENGLISH
They may have found their welcome here warmer than they would have liked if you had accompanied them. But it doesn't matter because it wasn't their business.
INTO JAPANESE
彼らはあなたが彼らに同行していた場合、彼らが望んでいたよりも暖かいここで彼らの歓迎を見つけたかもしれません。しかし、それは彼らのビジネスではなかったので、それは問題ではありません。
BACK INTO ENGLISH
They may have found their welcome here warmer than they would have liked if you had accompanied them. But it doesn't matter because it wasn't their business.
You should move to Japan!