Who is Tsaytl from Tevye the Dairyman and the Railroad Stories and what is their importance?

Tsaytl is Tevye's eldest daughter. She falls in love with Motl Komsoyl the tailor and secretly agrees with Motl to marry. She cries bitterly when she hears that Tevye has arranged for her to marry Layzar Wolf. Tevye is not willing to force her into an unhappy marriage.