When English speakers don't understand a sentence or a language they usually say, "It's all Greek to me". In similar cases Greeks say, " this is Chinese". So is Greek one of the hardest languages to learn?Well, if you are an English speaker the answer is "no".
Each learner is different.The time learners need to achieve language proficiency depends on a number of factors.The first factor is how close is the learner's native language to the new language. For instance, for an English speaker it is easier to learn French than Japanese.Another important factor is the complexity of the new language. It is true that some languages have complex grammar or syntax. For example the Japanese language has three writing systems. So, the new language may seem difficult but if you learn it step by step you should not be afraid.
Furthermore, we can't say that a language is difficult if we don't devote a sufficient amount of time to learning it.Besides, the learning method, the resources and the material that learners have access to affects the degree of difficulty.
Last but not least, the more motivated to learn the new language you are, the easier you will find it. So, why do you hesitate? Just do it in the right way.