Yes, it's too powerful to resist

The longer you fight your darker nature the more you struggle with discerning fiction from reality. You become more and more blinded by your fear, passion, and jealousy. You must keep Luna for yourself.

"Teach me your spell so that I might convince her to love me," you demand.

The voice returns, "The spell's trigger word is 'obey'. Focus your darkest thoughts, channel them into your magic, then think the trigger word, and she shall believe whatever you ask of her is what she wishes to think, say, or do."

You do as the voice says. Channeling your darkest thoughts and allowing the walls in your mind to crumble. You look at your hands. The green aura forming around them is tainted with black. You look back at Luna, summon all your strength, then think, "obey". Suddenly Luna's eyes go into a blank stare. She sits silently, not moving. She must be waiting for your direction.