a mind fuck is when a girl is confused and cannot give a boy the answer he wants
mindfucking is the verb form of that
most of the time, unfortunately, the girl has no idea what she is doing, and the more she tries to explain herself, the more inconsistent she becomes and the more confused he becomes. in the end, both normally realize they are mindfucking over nothing at all. nothing at all. unfortunately, the endings most probably aren't happy ones.
here is an example of a mindfuck:
Boy loves girl and girl loves boy. Boy will change life for girl and move to other state for her. Girl doesn't want that. But girl wants him. Boy thinks he is just getting a mindfucking. When really Girl just doesnt want to disappoint or commit. Girl still likes Boy and Boy still like Girl. But now the relationship is HINDERed.