YOU SAID:

I'm coming, too, if for no other reason than to keep you two out of trouble.

INTO JAPANESE

お二人をトラブルから守る以外の理由がなければ、私も来ます。

BACK INTO ENGLISH

If there is no other reason than to protect you both from trouble, I will also come.

INTO JAPANESE

お二人をトラブルから守る以外に理由がなければ、私も来ます。

BACK INTO ENGLISH

If there is no other reason than to protect you both from trouble, I will also come.