To have knowledge or information about something.

To be aware of something or to recognize it.

जानना

English Usage: She knows the answer to the question.

Hindi Usage: उसे उस सवाल का जवाब जानती है।

To be sure or certain about something.

सुनिश्चित होना

English Usage: She knows for sure that he will come.

Hindi Usage: उसे निश्चित है कि वह आएगा।