Okay something strange. I just had the translate from English exercise and it said I used the wrong word for save: it told me I should have written אני מצילה אותן but I have no idea what מצילה is. I have never seen the word before. Last time I had this exercise, שומר was fine.
Memrise translates this as "guard / keep." I can see how that could mean "save" in certain contexts but I like Memrise's translation better as it seems to be a bit more precise/narrow in meaning. Anyone disagree?
I believe שומר Translates Best to: Guardian or Watchman. But could be used to describe some form of watching guarding saving protecting etc... Also in more religious contexts it can be used to refer to a chaperone.
Here it is obviously a verb, so it can't be translated as "guardian". Also, in order for it to mean "I guard/watch them" it would need a different preposition - אני שומר עליהם. This way it means "I keep/save them".