97 honda accord ex v6 shakes when braking over 60 mph

Hi, I'm thinking of buying a 97 honda accord ex v6 with 100k miles on
it. I like it just fine, the only problem is is that it shakes quite
noticeably when i brake on the highway over 60. Is this something that
must be fixed or is it likely that the car is safe with this problem
(brakes won't fail?) I'm taking it to a mechanic, but if the owner
doesn't reduce the price by the amount it costs to fix the problem
should i still get it? I plan to sell it in about two years, and will
mostly use it to commute to work along the freeways.

Suggestions would be appricated.

Thank very much.