It helps you understand the user problem you are trying to solve, it tells you who your users are. In what context users will be using the product, in other words what they need from you.
ux research ensures that you are designing with your user's in mind.
It pays attention on your user's need, goals and their mental models.
UX research is the mandatory design process before you start designing. Without ux research you are creating your design's on the basis of assumptions, which can be highly risky in long run.
Your design should solve the pain areas of the user. Therefore you should engage with real users. The research phase ensures you are designing with actual insights and data facts not guesswork
UX research gives you a confidence in ensuring your designs are based on real users and their needs.