If you apply for a B2 at the embassy, but don't mention the overstay, what will be the reason you give for not applying for a visa waiver???

No, the person lied to you. The person is allowed to lie to you. If you have a 10 year ban from the US and you attempt to enter the US, you will be put in detention, and sent home... with a lifetime ban from the US. Do yourself a favor... don't be an idiot.

Ian

Some immigrant waivers require extreme hardship but he requirements for the waiver to visit aren't as severe as you describe. The reasons don't have to be so exceptional. They will way the severity and recency of the violation against the risk to the US and the likelihood that the person will violate again.

Thanks for answers,but i still don't know why ESTA is approved. Also if i fill waiver of inadmissibility but i don't have a citizen or resident wife and parents in USA - Can i be admitted to USA?

Because the system isn't foolproof or 100% accurate and mistakes get made. It doesn't matter anyway because you are not allowed to use ESTA by virtue of having previously overstayed. Your "approved" ESTA is essentially worthless.

You don't "fill waiver of inadmissibility" for a B2. You apply for the visa first and if the application is denied then the embassy decide whether to recommend you for the waiver or not.

I'd say you have a very small chance of being allowed, legally, into the US anytime soon.