The two rappers both went to the same LaGuardia High School in New York but have feuded for years.
In some gushing text messages posted on Instagram, she said: "Now I'm growing up, I'm realising a lot about what it takes to be a strong woman."
Azealia said she "cried a bit" when she saw Nicki's reply.
The trouble between the two begun back in 2012.
