Back testing reliability

Hello Mates,

I have those pretty unrealistic profit results after backtesting past 4 years in cTrader.

How much can I rely on the  backtesting results?
On the other hand it is my first profitable AIBot whch actually shows profit when backtesting.

So Im not certain what to think of what real is and what not.

Are there any ways to backtest in a “more realistic” way? 

Thank you!!!