That was… a… (ugh) strange thing to say. Did he mean to go off and come back? That would prove he had no fear of letting Nebula be in the wind. Did he truly know Gamora and know she'd agree? Or mean to bring her against her will? (He could try.) Either way… it was not the suggestion of someone trying to trap or trick.
If there was some magic afoot… then at least there would be two against one.
Unless he was about to present her with something that used to be Gamora but…
…Stop. At this point, can't anticipate, must react.
Nebula leaned back on one heel and folded her arms across her chest. "All right. Bring her."