Why do girls always say "you will get someone better than me" rather than excepting the proposal?

I have always been elusive and perplexed of this peculiar phrase "you will get someone better than me". If that is so why are girls rejecting the guy because a girl is getting more than she asked for. Isn't that the logical way. ?
Why do girls always say you will get someone better than me rather than excepting the proposal?
Updates
+1 y
Why do girls always say "you will someone better than me" rather than accepting the proposal?
Why do girls always say "you will get someone better than me" rather than excepting the proposal?
Post Opinion