As Muslims, we should try our best to stay away from committing any act that is likely to drive us to the realm of the unlawful. We should stick to our Islamic morals and refrain from being a tool to achieve something that is originally unlawful in Islam such as the case referred to in the question. With this, we will be on the safe side regarding our religion.
Dr. Ahmad Shleibak, Member of the Fiqh Council of North America and Member of the Assembly of Muslim Jurists in America (AMJA), states the following: There will be no problem if a person wants to help others to get a loan as long as it is interest-free, and the person will be rewarded by Allah for that. However, it is not permissible to help others get an interest-based loan unless there is a necessity that the person must have the loan and he or she cannot get it through a halal way. The person must repay that interest loan as fast as he or she can in order to reduce the interest that he or she has to pay, and must try to find another source to pay off that loan.
However, helping others by translating for them so that they can get an interest-based loan is only permissible in the case of necessity; otherwise it will be forbidden and the translator will be sinful and must seek forgiveness from Allah.
To repent from this one is to stop helping others get interest-based loans and feel deeply sorry for the translation that one made and then promise Allah never to do it again. Then one must ask Allah for forgiveness and for help to never slip into the same sin again.