SQL-Server database health-check I'm new one with SQL Server, and I have the following question:

My database is not big, about 1 GB, and I make regular backups with the help of third party tool. How can I be sure that if a failure occurs I will be able to restore my database with the minimal loss?
The only way to be 100% certain is to restore the backups. If you are restoring to the same SQL Server instance then you will want to restore with a new database name and make use of the MOVE restore syntax to restore the .mdf and .ldf files to a different directory. 

Alternatively, you can restore to a separate SQL server instance with the same database name. Again you will need to consider if the MOVE syntax is relevant.

See Retore SQL Server database to different filenames and locations for help. 

For added piece of mind, you should create all your backups with checksum and after validate the metadata consistency with a RESTORE VERIFYONLY check. The restore verify can be automated by using using Ola Hallengrens excellent backup solution SQL Server Maintenance Solution