The 2-minute check
Before depositing: (1) is the licence shown in the footer, with a number? (2) is the connection HTTPS? (3) are the bonus terms published and readable? (4) is there a responsible-gambling page with limits and self-exclusion? (5) does support reply before you deposit?
If any of those fails, find another brand. There is no shortage of options.
Research the reputation
Search the brand on independent complaint platforms and read the negative reports for a pattern: is the problem always withdrawals? always verification? Is the company's reply boilerplate or does it actually resolve things?
A very new brand has little history — that is neither good nor bad, it is a reason to start small.
Protect yourself while you play
Set a deposit and time limit at the start. Use the same method to deposit and withdraw. Do not chase losses. If betting has stopped being fun, use the brand's self-exclusion and seek support.