Marriages that are passionate are the ones when each person realizes that passion is created rather than it simply happens. So often singles think that if
they simply pick the right person, they'll have a wonderful marriage.
I agree who you marry is important, but even if you pick the perfect match you'll still need to live with them day to day. There will be circumstances that are scary and depressing, no matter how attractive they are.
After working with couples in marriage counseling for over 20 years, I can tell you what will mean the most to you. Not what should mean the most...but what will mean the most. It is a person's character. Are they kind, do they keep their word, etc. There is nothing more important that knowing you can count on your spouse.