Am selling my btc account containing 0.3 btc for ethereum if it is a reputable member I go first
Unless you can withdraw funds to another wallet address (non custodial), it is probably a scam.
Please provide more details so that I can better understand your offer.
Most likely is a scam.
I am sure he going to ask you to register for an account on a platform and send you the BTC, thinking you'd send on-chain ETH to his/her wallet address.
It's better to avoid a transaction like this with OP judging by the post history the account.