Some boy b got rejected by his optimal girl g because she said “maybe” to a preferred b*. b* likes g at least as much as his optimal girl.
There must exist a stable paring S in which b and g are married.
- b* wants g more than his wife in S
- g is as at least as good as his best and he does not have her in stable pairing S
- g wants b* more than her husband in S
- b is her husband in S and she rejects him for b* in TMA