Why does she want it when she doesn't know what it means?
This is my thinking too. Personally, I hate tattoos, but this isn't about me here. I just wonder if it's the tattoo equivalent of the baby name Nevaeh, which as has often been mentioned on here, ends up with the name becoming de facto 'Nevaeh It's heaven Spelt Backwards'.
If you: want the esoteric value of it/special significance to yourself; only want it for yourself and want almost everybody else not to know what it means; or you maybe want the attention and the opportunity (which may get extremely wearing before long) to explain to everybody what it means, when they invariably ask, all well and good.
However, if it were me - I would never have a tattoo myself, but maybe if I had it on a t-shirt or piece of artwork - as a native English speaker living in England, if I wanted something saying 'Dare', I would have the word 'Dare' - in English. I don't get why you'd go to the trouble of having it in a language which neither you nor almost all of the people in your country/community speak, and end up having to explain it to everybody. If they see 'Dare' written on your arm (or wherever), they clearly get the bold message that you're wanting to portray, the nuances of which you can interpret themselves; if they have to ask you what it means (and maybe why you had it written in a foreign-to-you language), surely a great deal of the impact has then been lost?
Additionally, as a living language, I presume that Japanese is fluid and meanings or understandings of words may well change. How could you know that it wouldn't now/ever have different connotations to Japanese speakers? It's not a great analogy, but I'm thinking e.g. if a non-English speaker was a great admirer of hymn-writer Fanny Crosby, cookery expert Fanny Craddock or any other famous woman in history with that name, and so had 'Fanny' in English tattooed down their arm. They know what their completely sincere intention is, but any modern English speaker would maybe interpret it a little differently....