honeymoon period

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A relatively brief period when a new leader is given greater leeway with respect to changes he or she wishes to make.
• noun finance A relatively brief period when a new loan has a low introductory interest rate that features prominently in advertising.
• noun The length of time at the start of something new, particularly a new job, in which mistakes may be overlooked.