YOU SAID:

i'm alone, i can swear for real

INTO JAPANESE

私は一人で、本当に誓うことができます

BACK INTO ENGLISH

I can swear by myself really

INTO JAPANESE

私は本当に自分で誓うことができます

BACK INTO ENGLISH

I really can swear myself

INTO JAPANESE

私は本当に自分自身を誓うことができます

BACK INTO ENGLISH

I really can swear myself