“在新的一年里，我要不让大家失望，努力做到最好的自己”译为英文

i will not let you guys down and try to do my best in the coming year.这句话比较口语，如果是很正式的用disppoint

In the coming year,I won't disppoint everyone, and I wil try my best.
符合你的意思噢~-~

In the new year,I will not disappointed by others and do my best.