Answer:
He made this statement because he believed that learning to ride a bicycle was a big challenge and that someone could die doing it, as it had happened before, but riding a bicycle was very pleasant after the individual learned how to handle it.
Step-by-step explanation:
Samuel Clemens died riding a bicycle, before Mark Twain wrote the passage shown in the question above. It is likely that Twain made a reference to this incident, but with the characteristic humor of his works.
Twain understood that riding a bike was a big challenge, it required a lot of control and balance, and that at any moment an individual could lose control of the bike by fatally injuring himself, however, he believed that the bike rides were very pleasant and that no one would stay sorry to have such a ride, if they survived, of course.