A teacher in 30 vies asks a student a question. The student takes the question too personally and gets upset. Surprised about how the student overreacts, the teacher says to her:
Capote pas! […] Coudonc, tu réagis donc ben fort.
With capote pas!, the teacher was telling her to relax, to not lose it. (The verb is capoter.) Coudonc shows his surprise, maybe something like “jeez” in English. Tu réagis donc ben fort is “you’re really overreacting.”
You can learn donc ben as an expression because these two words are often used together to mean “very.” It’s an informal use.
Some pronunciation help — here’s how this quote could be written a little more phonetically:
Capote pas! Coudon, tu réagis don bin fort.
[Quote from 30 vies, season 2, episode 93, Radio-Canada, Montreal, 5 March 2012.]