What is everyone's speculation and bet? Will America enter the middle east or not? According to Polymarket, the rating of America's entry on this war is 45%.

US is not dumb to enter on the war themselves unless Iran poke them directly.
US is doing proxy war for a long time against Russia so it’s impossible for them to risk their position while they can be profitable at the sidelines by selling weapons to Israel.
So no is the answer but ofc there’s still a small possibility tho.