There's absolutely no on screen evidence that Saavik is part Romulan.
But it’s a helpful approach to rationalize her tears at the end of ST II: TWOK, because shedding tears would be totally distasteful and out of character for any educated Vulcan.
Mr. Laser Beam wrote:
And also remember that there's absolutely no reason to believe anything Sela says. Just look at her attitude; she willingly betrayed her mother to death, and anyone who does that, can't be trusted.
Where is any evidence for that claim? Ron Moore’s audio commentary on the “Redemption” Blu-ray disc makes it rather clear that Sela’s account is genuine and accurate, because that’s how TPTB wanted it to be.
Before we start double-guessing the statements of protagonists (and especially in this particular episode
), we should present good reasons to do so. I’m not aware that the TNG writers deliberately introduced ambiguous statements to confuse the audience.
And I look at her attitude – that of a four year old child
that understood it was going to be separated from his daddy and didn’t want that to be happening.
What I get from the Sela scene in “Redemption II” is that she actually regrets what happened to her mother, but couldn’t possibly say so in front of Picard. Therefore she puts all the blame on her mother (not convincingly enough, apparently, if you look at Picard’s reaction – I love this scene, one of the best TNG has to offer).