お～になる (or
ご～になる) is a 尊敬語（そんけいご） (honorific speech) expression which is used to pay respect to the actions of the person that is being spoken to/another person (never the speaker). In this expression,
になる is used in exactly the same way that
する would be, except that it will be attached to the ます stem of the verb that it is referring to.
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お客様（きゃくさま）がお見（み）えになるのは3時（じ）頃（ごろ）です。
The time that the customers will come will be around 3 o’clock.
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皆様（みなさま）、お立ちになってください。
We request that everyone stand up.
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この資料（しりょう）がご参考（さんこう）になれば幸（さいわ）いです。
It would bring me great happiness if this document could be a useful reference for you.
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部長（ぶちょう）はどういう番組（ばんぐみ）をご覧（らん）になるのですか？
Boss, what kind of TV shows do you watch?
The primary difference between お and ご, is that お will be used with words/readings of Japanese origin (kun-yomi), and ご will be used with words/readings of Chinese origin (on-yomi). In fact, お and ご are both represented by the same kanji. For this kanji, 御（お） is one of the kun-yomi, and 御（ご） is one of the on-yomi.
Some verbs, like いでる, are used almost exclusively with 尊敬語（そんけいご）. おいでになる (the お～になる form of いでる) is an example of this, and can mean ‘to come’, ‘to go’, or ‘to be’. This is due to the perspective of the speaker when using 尊敬語（そんけいご）, and something that we will discuss in more detail later.