I would like to know which of the two words 'true' and 'real' is fine to put in the following sentences.
1. True/Real friendship takes time to develop.
2. The pair shoes are made of real/true leather.
3. What is your real/true name.
4. That is the real/true reason why I want to resign the job.
5. A story of real/true life.
6. She is trying to find her real/true father.
"Real" is either something that exists and can be proved to exist without doubt. You can observe it and so can everyone else. "Real" does not always mean "true" - you can tell lies that are "real" lies, but not "true".
"True" is something that is believed by the user to be correct but may not be proven beyond all doubt by the user of the word, so it is up to the listener to determine for themselves whether the state of truth actually exists.
"what is truth?"....it is what someone believes to be true.