No, no legitimate casino will ask you for $100 for account verification.
If you miraculously won some insane amount of money from a no-deposit welcome bonus, that is also a strong indicator of a scam. Legitimate casinos limit the maximum withdrawable amount from such bonuses, usually to somewhere between $50 and $150.
As Afi4wins mentioned, casinos generally require one deposit before they process the first payout. However, a minimum deposit is sufficient, which is usually in the range of $10–$20.
Search for the casino on AskGamblers, and if you cannot find it featured on the site, you should be extra cautious. That does not mean a site featured there is automatically trustworthy, nor does it mean a site not featured there is automatically a scam. Still, it is a good starting point.
If you actually shared the name of the site, we could tell you for sure whether it is a scam or not. However, based on everything you have told us, which is not much, it is most probably a scam. Do not pay them.
@mhjahidkb Hi there and welcome to the forum.
In most cases, legitimate casinos would only require a minimum deposit of around 20 - 25 EUR to verify and process a new account.
There have already been so many reports of crypto casinos demanding a 1st initial $100 deposit just to get the new account verified, but more deposits would then be demanded just to get the withdrawal claim processed - needless to say, most of these crypto casinos are scam ones!