You can check their contract address, most of the projects got their contract address so that's part of checking if the funds were there and secured by the development team. But why are you making that sure that it's safe? you should always be active on their telegram or any means of communication with their community because they're the ones that will answer on how you'll check if the funds of the project are there. There would always be a way to contact them and ask your question directly. For example, what's the current project that made you ask this question? you contact them and this question directly to them.