It's not hard.
Step 1 : know what to look for in the person you want to be with( don't have too many hard requirements and don't consider looks like 6ft, handsome etc into hard requirements) - this is indeed hard if you don't know what kind of man you want
Step 2 : discuss what kind of life you envision. Take time to know each other. The quirks, the nice things, the things that you need to adjust with each other. Understand if you match each other's expectations, understand behavior traits - empathy, comfort, communication, anger, toxicity etc. Find out if you Match on emotional, physical and psychological level
Step 3 - once you know these things, you'll be able to make out if you wanna spend rest of your life with this man. If not, move on!
This is by far best way to decide where you have complete control over how you want the marriage to turn out