Desire form verbs (~たい), is there a polite form?

Question

I was just curious if there is a way to make the ~たい form polite? for example

戦いたい - Want to fight

I was thinking possibly using the honorific form instead of the masu form might be acceptable?

お戦いになりたい

Answer 1

I assume you mean the honorific form, rather than the simple polite form (which can be achieved by just adding です after 戦いたい).

お戦いになりたい sounds odd in most cases, because ～たい itself is usually for a desire of your own. Honorific expressions are for someone higher than you.

• https://japanese.stackexchange.com/a/3844/5010
• Can たい and たがる be used for a 1st/2nd/3rd person's desire?

The natural honorific version would be 「将軍は戦いたがっていらっしゃる」「将軍は戦いたがっておいでだ」 etc. You can still use plain たい before other certain honorific expressions: 「将軍は戦いたいと考えていらっしゃる」, 「将軍は戦いたいと仰っている」.

As you can see in the second link above, there are cases where ～たい can be used for 3rd party's desire. For example I think 「将軍がお戦いになりたい理由が分かりません」 (="I don't understand the reason why General wants to fight") is not incorrect, although I still feel this is slightly awkward.

Answer 2

My thought is as follows:
There are two types of paradigm.
たい is a adjective form that shows a state of a subjective will.
たがる is a verb form that shows a state from an objective viewpoint.

 私は戦いたいです。　　　　　　　I want to fight.
 あなたは戦いたがっています。　　You want to fight.

 私は戦いたくありません。　　　　I don't want to fight.
 あなたは戦いたがっていません。　You don't want to fight.

 私は戦いたいですか。　　　　　　(impossible sentence)
 あなたは戦いたいですか。　　　　Do you want to fight?
 彼は戦いたがっていますか。　　　Does he want to fight?

Therefore,
because to ask directly other person's will is rude as the honorific form, I think たい is rarely used.