Love/Fear

This is a question out of curiousity for those that are married. Do those that are marriage marry out of love or fear of an individual or both? I know that marriage is a sign or love and understanding of an individual. There are times that people tend to not trust that individual with no one around them. So to prevent that, they marry that individual to prevent from losing them. This only applies to some. Not all. So what do you think about this?