Mrs. ...  was a devoted teacher in a school. At some point she was being pressured by another school to change jobs. Mrs.  ...  was uncertain whether to continue in the current school or take the new opportunity which had more favorable conditions.

The Rebbe answered in a letter: (free translation)

… Regarding the field of Chinuch, there is a very important and main point:  many times it is very hard to estimate the potential of the students and where it will lead them in the future. Meaning that even those that look like simple students at first glance, it's very possible that talents will be revealed by them or such perseverance and diligence that they will be successful in the learning and behavior much more than the capable and talented students, and they will end up being the pride of the school and teachers. 

As we saw in the past the great effect of the power of persistence even when the capabilities were simple. And how out of ordinary capabilities were revealed that which couldn't be imagined before.

Especially in the school that you are working in until now, it seems from your description that it fits the מאמר חז”ל  that הזהרו  בבני עניים שמהם תצא תורה— and regarding this school you have a special responsibility and obviously a special pull because it's natural that a person cares for whatever he worked on. 

From all of the above you can understand my opinion that you should continue working in the school that you have the holy position until now with strong hope and Bitachon, and for sure your devotion to the above work would be the channel and vessel to added success in your Avoda, and added Bracha also in your private things and the things of your family that you requested and will be mention at the holy Tzion of the Frierdiker Rebbe that the school is named after him and being one with his spirit.

With blessings for good news in all of the above.

# 2 Chinuch Gems