So first of as already mentioned save your game before you pop the question! Both before proposing and before talking about dowry.
Second, millionaire? I paid under 4000 for dowry, just a formality.
Third, Charm does matter, mine was level 36 when I proposed. I don't know what it should be but the higher the better.
Fourth, I belonged to no faction and had no fiefs when I got married to Abagai, so in this scenario it does not seem to matter in what faction you are looking or that you have property. If you already belong to a faction it may be different I don't know, but it stands to reason that you can only look in a friendly faction where you are liked.
Lastly in case you did not know there seems to be an age limit for males to be eligible, it is 35 according to other posts. I hope they will change that as it is way too young imo. So the game does not indicate this but there is pressure to get married early on but your timing in terms of charm stats and age has to be just right. I just got it all perfectly lined up by chance.