If a girl is dating a guy she wants to marry, does withholding sex until she is engaged increase or decrease the probability that he will propose?

If a girl is dating a guy she wants to marry, does withholding sex until she is engaged increase or decrease the probability that he will propose?
Updates
1 y
Unless she has been in a known sexual relationship, if a girl is withholding sex, the statement "If she is a virgin" is not relevant because the guy has no way of knowing whether or not she is a virgin. First, she is not likely to truthfully volunteer that information, and second, boyfriends that value the relationship don't ask.
Updates
1 y
The try before you buy argument is not applicable and is not valid for sex before a commitment. Moreover, men who insist on sex before a commitment have limited their choices for marriage to hoes.
If a girl is dating a guy she wants to marry, does withholding sex until she is engaged increase or decrease the probability that he will propose?
Post Opinion