Objective
な adjective
Remember 主観的 meaning "subjective"? This is the counterpart to that. And since guests' and customers' views are always objectively right, this means objective.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
これは客観的事実です。
This is an objective fact.
客観的に見て、今の発言はおかしいです。
Objectively speaking, what you just said is not right.
客観的なデータがないと説得力に欠けてしまいます。
Without objective data, it lacks persuasiveness.