Is the beta version of MacOS Catalina safe?

Certainly! Please provide the text in the Unknown Language that you would like translated into English.

While the beta, especially at this time, is relatively safe and relatively stable, it wouldn't be appropriate for production use. Typically for vendors that don't keep everything perennially in "beta", beta should be seen for dev/qa uses, not as a production environment. Wide-release comes with wide support. If you run into issues with a production environment that is running beta software, expect the vendor response, if any, to be "wait for the release." So.. if you want to play, need to test, or want to get ahead of things for knowing about if your workflows will keep working on Catalina, go for it. If you need to run your business and have questions about compatibility (e.g. 32-bit support), stability, or safety, wait for the release and check with your 3rd party vendors about supported versions. Either choice is reasonable depending on your reasons.

Simon makes the most important point here, in that your 32-bit support ends with Catalina. If you have a Mac that is more than a couple of years old, even if Apple says it is compatible, I would hold off - and if you do update, back up everything so you can revert. To actually answer the question you asked, though... Generally, yes - Apple betas are quite safe. The only time I have ever run into an issue with betas is when I am attempting to run something just on the edge of the hardware's capabilities. To that end, the rule should always be - "Back it up before you update it!" If you do not like the way the machine runs, you can always revert back. Best of luck!

Well, not that much if you are using old school applications that may not have been updated. Since Catalina is completely dropping 32 bits application support, you may have some big surprise here! In my company we have several applications that are business critical and that are 6-7 years old and no longer updated, so we will never be able to go Catalina for this reason. Just think about it.