In my opinion, trading is best option because through trading we shall become expert. In future, people will show trust on us and they will give us money to invest and make 50-50 percent profit. In this way, we can invest other money and can get a huge profit because every person investment plans are different. Some people can invest 100000$ but they don't have skills, in this way we can help these persons and we can make a huge profit. If we have skills, we can invest own money and can get good return on investment. But in case of gambling this is not possible, there is no learning, no skills and no experience. One day you can win and will be king and next day you will be on road, if you lose.
You are very sure that trading will provide profit especially if you are an expert, and in that way intend to provide opportunities for other people who want to put their funds in you with a 50-50 profit share, even though nothing is certain in trading even though you are an expert, you will still have the opportunity to experience losses and when you experience a loss people who put their money in you certainly won't like it and usually people who are willing to put their money in other people because they think they will get a definite profit and really don't understand what trading is. So trading is no less risky than gambling so you have to be aware of that and always use money you can afford to lose.