Is it permissible for me to look at Russian sisters when teaching them matters of their religion due to the lack of an alternative, knowing that necessity dictates looking at them in order to make them understand?

Allah Almighty commanded lowering the gaze from non-mahram women, and the Sharia prohibited everything that leads to temptation, such as intermingling (ikhtilat) and private seclusion (khalwa). Calling to Allah does not permit what Allah has forbidden, and the caller (da'i) must be a good role model. Therefore, it is not permissible to look at non-mahram women or intermingle with them. Methods of calling women (to Islam) are possible without that, such as through women themselves or their mahrams, and if necessary, in a permissible way that does not require looking at the woman's face.