Negima!? Magister Negi Magi Episode 12: After Much Quibbling, in the End All It Comes Down to Is How You Feel.
Episode 12 of 26 of Negima!? Magister Negi Magi, aired December 20, 2006, 25 minutes. Available with English subtitles and dub where released.
Episode summary
Yue has found out about Negi being a mage but refuses to form a pactio with him. Can Negi form a pactio with Yue before Shichimi and Motsu find out that Negi's secret is out?