When used in the preterite tense, the verb "saber" means to find out.
In a present tense, ther verb saber would mean to know. However, It can change its meaning when conjugated in its preterite form: supe or sabía.
In this case, "supe" in English could be translated as found out into English when refering that you learnt or got specific information about a person or about something.
Answer:
Dear mom,
I hope ur well. I am also fine,I want to tell you something very important.today a new girl came to our class and now we have become friends.Her name is lusy,she speaks very politely and her behaviors are also very nice and I think she is also very good at studies.
your lovingly,
name
