There are many variables to consider when determining which language is the easiest to learn. For native English speakers, the easiest languages are generally those from Western Europe, such as French, Spanish, or Italian. These languages share many cognates with English, so they are easier for English speakers to pick up. Other factors that can make a language easier to learn include its similarity to your native tongue and the amount of available resources (such as learning materials and conversation partners).
That being said, there is no standardized answer as to which language is the easiest to learn. It depends on the individual learner and their specific goals and needs. Some people may find Mandarin Chinese incredibly difficult due to its tonal nature and complex writing system, while others may find it relatively easy because of its logical grammar rules. Ultimately, the best way to determine how difficult (or easy) a particular language is for you is simply by starting to learn it yourself!