Bearing in mind the Mitzvah "Ki Im Besulah me'Amav Yikach Ishah" (Pasuk 14), what is this Pasuk coming to teach us?
Why does it say "bi'Vsuleha"?
R. Meir (Yevamos 59a): Besuleha implies that she has all her Besulim, but not a Bogeres, whose Besulim fall out. Bi'Vsuleha shows that the concern for is only for the place of Besulim (Bi'ah Lo k'Darkah would not disqualify her).
R. Eliezer and R. Shimon (Yevamos 59a): Besuleha implies even some Besulim, e.g. a Bogeres. Bi'Vsuleha shows that she must be a total virgin (she did not have Bi'ah even Lo k'Darkah