No one can be sure of anything, otherwise, everyone would've become rich.
The signals that are offered by some services and telegram bots usually predict the price increases based on the sudden increases in trading volume.
I too not recommended going through bots for calls.
What instead someone can do is buy paid signals from some veteran trader.
I know the predictions are not 100% sure, but to make it even more easier, you can go for free calls.
Now you can get free calls from twitter itself.
Hope this helps you OP.