If I take an internship abroad in Europe, will I be lonely if I go alone? Or will it be as fun and party-like as advertised?

I have an option next year to take an internship in Belgium. I would go alone. It’s a great work opportunity and I really would love to get out to Europe, but I’m afraid it won’t be as I imagined it to be? Like when I look online I see people having the time of their lives, meeting locals and partying and experiencing so much. But then one of my friends said it wasn’t like that for her. She said she got super lonely and it wasn’t easy to just meet anyone. She said she made a couple friends but nothing where she went out and partied and had the time of her life. What’s realistic here/what should I expect?
If I take an internship abroad in Europe, will I be lonely if I go alone? Or will it be as fun and party-like as advertised?
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