Like when there is a "challenge" or a "mission" you can "accomplish" it. What word can you use for a dare. When I dare a person to do something and he does it what does he "do". "dare accomplished"? (I am looking for a better word than accomplished)
As with any commitment, you can honour a dare.
fulfil (an obligation) or keep (an agreement):
In US English there is a phrase take a dare that means
be dared to do something and attempt it
There are numerous references in literature with this meaning, as the citations behind this ngram reflect. The sense is to undertake a dare.
Unfortunately, to some people the phrase also may mean
be dared to do something and not attempt it [emphasis added]
The ngram also reflects that. The sense is to put up with [to take it].
Context is everything.
I might say that the person has completed the dare, in the same way that one might complete any other assignment:
1 : to bring to an end and especially into a perfected state <complete a painting>
People typically "follow through" their dares (and threats!)
definition of the idiomatic phrase: "follow through (with something)" and "follow something through":
to complete an activity, doing what was promised.
The answer has to be 'he dared'.
The verb 'to dare' in its original form is used in the sense 'John dared to jump in the lake', meaning that John was brave enough to jump in the lake.
But 'dare' in a different sense, 'I dare you to jump in the lake', meaning 'I challenge you to jump in the lake' has evolved. But it is a different verb, or the same verb used in a different sense. This verb also gives rise to the noun 'a dare'.
So when you dare someone to jump off a high building and they do it, you are using 'dare' in this second sense. And if they do it then they 'dared', in the first meaning of the verb.