"I'm not good at this either," she tol him, reaching for his hand and entwining her fingers with his comfortingly, remembering only at the last second to make sure Bellamy could feel the thrum of a pseudo-pulse through her fingers, and human warmth instead of cool pseudo-flesh. "I feel the same way." She told him softly, "you're by far the nicest guy of met in some time."
She let the moment linger for a moment before beaming widely, giving her best happy Cat smile. "That's nice! Oh I'm so glad you've got family here." She didn't need to say the 'unlike me' at the end, she 'covered' it well, but Bellamy should still be able to see the flash of sadness in her eyes under the smile.
"Clarke, is that the person you were talking about earlier?" She guessed, the tone of his voice similar to how he'd spoken earlier. "It sounds like you respect her a lot. Does your sister like her too?"
Perhaps a little divide and rule would work. Even if he didn't she was starting to get somewhere, gauge his relationships, so that she could break him. Gemini was by no means the expert her mother had been, but she'd been trained well, all it would take was time to worm herself deeper into Bellamy's life, learning as she went until she was ready to make his life burn.