Reveal Weakness doesn't affect it, it only increases damage taken by the MOB.
Perhaps you are thinking of Diversion? That'll turn them so their back is to you.
A key is to not move more than necessary in stealth, just like you are actually trying to keep hidden in shadows. Sneak up behind them, as soon as your skill is no longer out of range, stop moving and use it.
+stealth level just makes it like you are a higher level character in stealth, if you are being spotted with it, then you are either too close or not behind them. You can totally sneak up behind higher level MOBs and strike first from stealth, so I've never found +stealth level useful for PvE.
Hope this helps!
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