Frankly none of the four S factors would matter to me.
Does she have to be silly for me to marry her? No, not really.
Does she have to be serious for me to marry her? Well a little bit - she'd better be serious when she says "I do." But it's not a critical factor.
Does she have to be smart for me to marry her? No, not really.
Does she have to be sexy for me to marry her? No, not really.
Does she have to be witty for me to marry her? No, not really.
Does she have to be clever for me to marry her? No, not really.
Does she have to be athletic for me to marry her? No, not really.
Does she have to be kind for me to marry her? Yes.
"If a person is nice to you but rude to the waiter, that is not a nice person." Kindness is the only essential I can think of that really matters to me. Serious, silly, sexy, smart, don't really matter.
PLEASE NOTE: All this is coming from a 39 year old guy who has never even been on a date before... so what do I know about it?