This may look different for everyone depending on what feels “safe” for you, as well as what your needs are. There are some things that you may want to look for in someone that may be safe for you, such as someone who wants your mental and physical self to be taken care of at all times. Someone may feel be safe for you if they want you to win and to be the best you that is possible. If you feel good around this person, if you feel as if they won't cause you any harm, they may be safe for you.
Safe relationships usually involve trust and reciprocation. If someone is wanting to know all the things about you but does not share any information with you about who they are, they may not be a safe person for you, as your relationship is not balanced. If they are someone who cannot take a no and process it in a safe manner, they may not be safe for you. If something comes up with this person and they apologize but do not change their behavior, that may mean that they are not safe for you because they are not trying to adjust something that you have shared makes you uncomfortable.
Know that when someone acknowledges that their behavior is harmful, yet does not change the behavior, that is still manipulation. To make it simple, think about all the things that make you feel unsafe. Does this person that you are looking at do these things? If the answers are yes, then that person is probably not safe for you. If the answer is no, there is more of a chance that this person is for you.
Some signs of an unhealthy relationship include:
There are many other ways that you can find out if someone is unsafe for you. But these are a few ways to start reevaluating your situation.