What game will sonic admit that he likes Amy rose

Personally he doesn't have to admit it, he can show it. But if i had to pick, it'd probably be Sonic Adventure 2. Watch the part where Sonic enters a space prison with Eggman holding Tails and Amy prisoner. Listen to everything too; -) you'll see how Sonic responds to Amy when she's upset that he got trapped in a time capsule and he uses a chaos emerd to save his life. It can be found on after you beat stage 15 on Hero story and before the next boss (Tails fights Eggman after Sonic was set to die)