Rakes are killing all my scholars and priests. My assasins are no good. They can't even get rid of a fly. Saving and reloading doesn't do good for me (50+ save and reload and no kills with 5 assasins although the possibility is %25 for each one [which seems to mean "0/250=never!".])
Is it not possible to add an option of increasing stats of special units to the trainer? I remember using it in totalwar 2. It may be really helpful.
Firstly, learn your probability distributions. If you're unlucky, you'll get 5 heads in a row when you want tails.
Secondly, E:TW's random seed probability system does something funny when you load a saved game. This was to stop people from saving and reloading to get a different outcome from a fight.
My advice is to advance one turn and try to assassinate your target slightly later.