"The Confidence of Gotenks!!" (ゴテンクスに自信あり！！ Gotenkusu ni Jishin Ari!!, lit. "Gotenks' Got Confidence!!") is the four hundred eighty-ninth chapter of the Dragon Ball manga.
Kamesennin, Dende, Kuririn, and Bulma are trying to understand Piccolo's motive in guiding Super Buu to the Room of Spirit and Time. Since Trunks and Goten are not yet ready, and so on, they will probably lose. However, Dende assures the group that the room can be treated as a trap for Buu, and the Dragon Balls can be used to wish the boys back to life. Further, Kuririn comments that Piccolo is taking his time, so 1 minute in our world is 6 hours in the Room of Spirit and Time. Buu is getting more impatient, wondering why they have not reached the room yet.
Inside, the two boys are tired, and talking about having just finished a bout of fusion mode, and how it feels to go past Super Saiyan level. They discuss the advantages of training in the Room of Spirit and Time and having 1 week of extra training time. With glee, they envision being able to save all their friends and relatives with their great power. Piccolo contacts the boys telepathically to tell them that he is on his way to let Buu into the Room to fight them soon. Goten panics, stating that they just came out of fusion mode. Piccolo assures them that they have 6 hours to sleep and recover. They do this.
Piccolo asks Buu if he wants supper first. The monster angrily replies that he does not need to eat and that he is tired of all this messing around. They reach the door and go in. Buu looks around, commenting that it is a weird place. He finds the two boys waiting for him. They taunt the monster, but Buu is not impressed. Piccolo silently pleads for the boys to not screw up again. As they start the Fusion Dance, Buu loses his patience and bashes Trunks. Trunks yells at the monster to wait. Buu looks sullen. Goten and Trunks go through the dance, and, with a flash, they turn into Gotenks. Piccolo is happy and Buu waits while Gotenks continues bragging. Buu still is not impressed, while Piccolo believes that the boys have gotten a lot more power. Gotenks attacks Buu and has no effect. Gotenks wants to know what went wrong, and Piccolo does not know, either.