The sentiment melts over him, making his magic glow just a bit brighter. Monsters are weird. Love, compassion, hope, all of it was essential to keeping them in one piece. You lose that, you let your hope dwindle to nothing, you fall down. From there, it's only a matter of time until you turn to dust.

Sans leaned a little harder against Lara, squeezing the arm around her to match it. He would swear he had just a little more Hope than before. Even if it went back to one before too long, the brief burst of strength is... nice.

"M'glad it hurts less. 'Cuz..." He looked up from where he was holding her, not bothering to downplay his own protectiveness. A pure hallucination was one thing, and maybe that's all this was, but Sans trusted Lara. If she said it felt different, Sans believed her. And if there's even a small chance the specter could see him, well...

He'd better get it through his skull that Sans wasn't going to sit idly by. For once.

"I care about you too, kiddo."