What is better Automation testing or Manual Testing ?

Both is important. Automation helps a lot in Regression Testing. Backend automation helps a lot on the earlier stage of testing and help to improve the quality of the code, therefore less defects found.

if you have a huge regression test suite .then you should always look for automation since the management wouldn't want to be spending so many manual efforts in testing the regression test suite. For new enhancements,Yes we should be  testing it manually and then automating the same

It depends on the need since automated cannot test each and every functionalities  available in a software

Mostly Manual testing  is safer than the automated 

Both are best on their own. What really matters is the conditions/situations/scenarios you have. Based on those, you need to perform an activity to overlook the available resources you have, estimated time to complete that task, the tools you have available and expertise with that desired tool etc. These are some points you need to taken into consideration and after answering those questions you'll decide either to go with Manual testing or Test Automation using some tool.

Manual testing hands down because its more accurate