It depends on how you define INCEST, but
Whichever way you wanna watch it, there was a tricky-script reason why it took so long for a reasonable articulate guy to act for such a long while to the extent of letting his half-blood sister to become emotionally involved before saying what he had zillion of ways and moments to tell her the truth. It took a day for his girlfriend to warn him but his answer was outlandish for an experienced snake-oil trader : "I don't know how to say it".
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