I'd have to take a newspaper, printed after the time/year/event where I told them I'm from the future. Yes, they would most likely think it was a hoax and stuff like the death of Princess Diana years in the future was some kind of sick joke. It'd be extremely hard to convince them and they most likely would ask me to leave or even get a bit aggressive. Now it it happened to me as in someone said to me that they were from the year 2050 and I was a 90 year old living in a care home It'd probably freak me out BUT I wouldn't dismiss it! I'm open to all thoughts and experiences. 🤔
Personally, I'd have the time machine on hand and somehow persuade one or more to give a demonstration on. Or even not tell them what it is until it's too late.
I guess it would be difficult though as people are unpredictable idiots. 🙄
The best thing would be if a telly was on during a historical/notable event and you'd be able to say what was about to happen or something, or say the news before they say it on the TV or radio, but then again, who has the telly/radio on at a family gathering?
Make some predictions to them and then return when they happen. Or something.