Toradora!

Taiga and Ami are to compete in a 50-meter swimming race: if Ami wins, Ryuuji will go to her villa over summer break, leaving Taiga alone. Ryuuji helps Taiga practice. After Ryuuji insists that she wants to win for Yuusaku and that he would go to Ami's villa alone if she wanted, Taiga is furious and refuses to compete. Taiga shows up last minute for the competition. When Taiga's leg cramps during the race, Ryuuji jumps into the pool to stop her from continuing; however, Taiga declares that she wants to win for him, so Ryuuji lets her go. When Taiga is pushing for the lead, a few boys are pushed into the pool and Ryuuji is knocked out. Realizing that Ryuuji is in danger, Taiga turns around and goes to save him, losing the match. Afterwards, Ryuuji regains consciousness to see a shaken and angry Taiga who screams that Ryuuji is hers. As a result of Taiga losing the bet, Ami gets to take Ryuuji to her villa, but Taiga, Minori, and Yuusaku insist on going too. (Source: Wikipedia)