First you need to separate between your standing against others and others against you. If you want to make them love you, the best thing to do is to set it to 1 on both sides of the editor.
The editor uses -1 to 1 because it is saved that way. The -30 to 30 is just the in game interpretation of that values.
One thing I noticed though: The trainer does not take short time reputation changes into account. If you attack someone, the faction has a "booster" statement regarding you with a timely limited reputation change. To get rid of those, open the save in the raw editor and delete that line corresponding to the faction
Please make sure you have the following: