That rape theory is so fake. Can Ino not fight for herself now 
Hey, Bulma was almost sexually attacked by two soldiers back in the early days of Dragonball. If Kishi's admiration for Toriyama pervades his writing to the extent that he's adopting some of his character thematic traits and plot scenarios then an attractive female being threatened by some lecherous minions of Toneri's faction isn't out of the question. The romantic underpinnings of this movie with Toneri obsessing over Hinata and attempting to force an heir out of her arguably makes a scenario like this one with Ino easier to get away with.
It still doesn't account for Sai's inexplicit attraction for Ino or why he would choose to marry her. I don't see how a traumatic experience like this one would inspire him to develop feelings for her. From Ino's perspective it's understandable because she's fostered superficial and misguided cravings for her imitation of Sasuke since early Shippuden. In a moment of vulnerability when she's afraid for her life and Sai comes galloping out of nowhere to save her as her shining knight then she would hold greater incentive to be interested in him - that I can understand.
The flaw in this potential romance is that Sai has never expressed any sexual or romantic attractions for anyone period. He had an indecent sense of humour, but we could attribute that to his lack of social skills. Remember his lack of reaction when Konohamaru transformed into two sexualised women? Indifference. In fact, he provided more acknowledgement for the man and man erotic transformation.
Like much of the epilogue's set-up and characters in general, this pair-up between Sai and Ino was awkward and appeared almost literally out of nothing. I believe Kishi just sat down one day, contemplating how best to ensure that the InoShikaCho dynamic remains unbroken by marrying them off to random characters so that a potential romance couldn't blossom between any of the three. Yet another halfwitted decision made by the author.
Edited by Atheck, 23 November 2014 - 11:33 PM.