Best practise how to sync MS SQL 2014 DB with other DB

What is best practise if we have application using MS SQL DB and we would like to have backup if MS SQL not work? Our scenario: 1. We would like to use MS SQL DB (main). 2. If main SQL not work we would like to use different MS SQL DB with same data. 3. If main SQL work again, we need sync data back to main SQL DB. 4. There is not possible generate same data, because every record use UID. 5. We can use MS SQL 2014 or MS SQL 2012.

Failover Cluster is option, but are they any other options?

Maybe will help some web pages where are those situations described and recommend what is best in each situation.