for starters i think it helps to accept that the ideal partner doesn't exist. everyone has flaws on one way or another. the problem is that when you meet that seemingly ideal person some day, that person only looks ideal because you haven't seen their bad sides yet. i think it really helps to keep that in mind. better to deal with the devil you know, than starting over with an unknown.
for your problem, i would want to look closely what it is that makes you feel ambivalent after a few weeks. try giving it more time to see if you still feel like that. get to know each other better, plan your potential future life together to get an understanding what each of you want from a relationship. love alone is not enough.
I think my ambivalence comes from a lack of excitement while just casually socializing. I have plenty of best friends who are hilarious and fascinating, that by comparison I can feel quite empty with a woman who is otherwise quite a catch. I'm trying to give the current one more time because maybe it's a function of how familiar we are with eachother and the experiences we've shared. Romantic relationships as an adult can feel so contrived!
from my experience it definitely makes a difference how well we knew each other, whether it was easy to just hang out. when you don't know each other, there is a lot of insecurity as to how to interact, and what the other will allow or expect or find uncomfortable. i guess most people in that situation will be cautious as to not appear to try to move to quickly, and that may lead to the experience you had.
what i found helpful is to not focus on romantic dates but join group activities where there is no pressure to interact directly. your friends and her friends or even some other group that you both join for some activity. there is still plenty of opportunity to get to know each other that way, because you will see how each of you act around other people.
for your problem, i would want to look closely what it is that makes you feel ambivalent after a few weeks. try giving it more time to see if you still feel like that. get to know each other better, plan your potential future life together to get an understanding what each of you want from a relationship. love alone is not enough.