You will have to avoid talking about sex or flirting with her in a way that suggests that you just want sex from her.
You get her to trust you by making conversation with her that is focused on getting to know her better as a person.
If you do this consistently over time, you will be able to convince her that you are not just looking for sex from her and this understanding will also help her stop being mad at you.
Yes, it may take a few attempts at substantive conversation before she is able to respond without anger.
However, as long as you are consistent, she will not be able to stay mad and will eventually start responding to your attempts at having substantive conversations that are focused on getting to know her better as a person.