Not particularly well versed on RNGs, but I think that using Google's random number generator for a commercial gambling site is a questionable move, especially because players have no way of verifying their bets.
Most of the gambling sites I've visited have their own RNG algorithm and tool for bet verification, and to be honest, this is the first time I've seen a dice game that uses a third-party RNG. But hey it's just me

A check bet system will be available soon.
All numbers are generated by Google's random number generator.
How we can check its fairness if your game is based on Google's random number generator?
AFAIK google's random number generator is not provably fair, I believe there is no way to check the fairness.
I dont think it is a good start for you to use google's random number generator as you can generate the number as many as you can.
How can we verify that you use the first generated number after we place the bet?
Aside from the fairness issue, your website is not that attractive and how about your house edge?
Google RNG is provides truly random result and no one can predict its result based on its code design, No doubt about that. The main concern here is if the Casino is really using google RNG in there website since there’s no way to verify this matter just by checking the website since its no an open source. The OP already promised that he will provide a ay to verify all bets on his next update so let’s wait for his update and give him a chance. For now this Casino should not be consider safe to play and also I’m sure no one will risk depositing money by just playing dice game since dice game is very common on all Casino.