If you are hurt by someone, or you don't understand why a person is behaving how they are, or what made them say the thing they said how they said it, etc, ASK THEM WITH WORDS. Be curious, not accusatory. Inquire sincerely about the thing that is troubling you.
Say, "That hurt my feelings. Can you tell me what made you say that?"
"This behavior is unlike you and it's kind of freaking me out. Can you tell me what's bothering you?"
"I sense that things are off between us. Can you tell me what I've done to upset you?"
"I don't really understand what you meant by that. Can you say it a different way so I can make sure to get it right?"
"I would really like to talk about what's been going on in with our relationship. It hasn't felt good to me lately. Can you tell me how it feels to you?"
DO NOT just let hurt feelings and misunderstandings go unattended. That is how relationships fall apart; when tiny unhealed wounds are allowed to fester, they eventually become necrotic. Think about how this idea works in the body, as it is fairly analogous to the spirit of relationship.
I would also invite you to remember that most people do not intend to be hurtful even when they are. Most people are just out here doing their best to protect **themselves** from being hurt. Applying intention and value to the behavior and words of others without inquiry is unwise, as most people are honestly not putting very much care and thought into how they are affecting others.
When it is brought to their attention how they are impacting others, however, they have a choice to address the issues, or not. You are likely to receive much more accurate information via people's response to your hurt, rather than from the thing that caused the hurt. That is usually a function of misunderstanding, carelessness, and often just having no idea how they are being received. It's when you say "Can you tell me more about this" that they have the opportunity to recognize their impact, adjust their behavior or words, and have a more positive impact moving forward.
Sometimes people will be unable to hear how they were harmful, and will become defensive. They might lash out. They might doubledown on the hurtful thing or behavior and insist that it is exactly what they meant to do or say. They might gaslight you and make you feel like you don't have a right to your feelings. They might tell you all the things you did to *make* them do or say harmful things.
This response is not about you, so I would invite you to simply receive the information and move on. Don't take it personally. Understand that this person you care about may not be in a place where they can have a constructive conversation about their behavior. Perhaps they are not used to being approached with kindness and curiosity, and they believe they have to protect themselves from what feels like criticism. Perhaps they are simply in the habit of defensiveness and don't see a better way to resolve conflict.
The best thing you can do is model the behavior you want to see in others. Treat the people you love with unconditional positive regard, such that when they (usually unintentionally) cause you harm, you don't have to take it personally or react harshly. Practice using words to ask clarifying questions and approach conflict from a place of "how can we resolve this?" vs. "how can I hurt you back?" or worse, just giving up on the relationship and not giving people a chance to learn how to do it better.