Rabbi Akiva Tatz said that the first thing one must look for in a potential spouse is if they are attracted to the person. But one doesn’t have to have this special feeling to know for sure that that’s the right one and it’s normal to be hesitant even after engagement because that’s human nature.
It’s a bracha to have an instictive feeling that this is the right one but it doesn’t happen to most people. And having that initial magical feeling doesn’t guarantee a successful marriage.