There is a saying "if your fooled once, shame on him but if your fooled twice shame on you." People should consider researching or verifying if what they're investing in is legit or not, if the founder of the project really exist. In the end it's their own fault investing their money in too good to be true projects and expecting immediate gains.

Bitcoin will be able to survive in the future but to be with has value stable, if the value of bitcoin kept down and unstable then the possibility of bitcoin will survive would be very little because many will be users bitcoin stopped flow using bitcoin, and if it doesn’t have the user then bitcoin will end

Because in order to be economically strong, it is necessary to remain stable to protect its price policy to protect its investors and to find its true value even though it is lost from time to time. Altogether, Bitcoin is not concerned with the monetary policy but the high amount of Bitcoin in the hands of big whales will protect this stabilization.

I believe in bitcoin, because we have a chance to earn extra income easily. It helps us to solve our problem in our financial and it makes us rich in the future. Because the profit is good. In the future btc is already very popular in all world and most people are invested in bitcoin. It gives us bright future and it makes improves our ideas, so continue believe in bitcoin.

Will the past repeat itself again like it did last year with ripple where it gained over 1000% and then suddenly dropped down to just few cents, will you invest in ripple or not ?

I dont think bitcoin is the safest investment, its true that bitcoin got limited supply and the more adoption could make the price go higher, but now the problem lies in adoption, and some of the feature makes bitcoin not benefit the country, and the government able to ban bitcoin, with less adoption the price will fall down, and I personally think bitcoin is the most profitable investment but not the safest, decentralised investment safety cant win with centralised investment.

The same way you change anyone's mind about something -- education. Not everyone's opinion can be changed though as some people are just set in their ways regardless of facts or evidence (or the lack thereof). Take the religious for example. Despite how much of a convincing argument you make you're very unlikely to change their mind. Someone who is so against cyrpto for whatever reasons is also unlikely to change their mind, but it can be done via education, especially if they're intelligent and open-minded. When telling people about bitcoin don't ever sell it to them as a get rich quick scheme because that always sets off alarm bells and scares people off, but explain both the positives and negatives and the risks and rewards and let them decide for themselves whether it's something they want to invest or get involved with, but I don't think bitcoin is very everyone so take that into consideration.