"I have a cheap Dell monitor , will it work with Mac mini?
Dell SE2219H Full HD"
It has both HDMI and VGA ports.
Either one should be usable with the correct cable.
You didn't tell us WHICH Mini you have. Always mention this in your posts, because which Mini you have can determine which connection ports are available.
I would try HDMI first.
If you already have an HDMI cable, try that.
If that cable gives you problems, then I'd suggest a "High Speed HDMI 2.0" cable.
If THAT doesn't work, I'd suggest a USBc (Mini end) to HDMI cable/adapter.
And if even that doesn't work, try USBc (Mini) to the VGA port (display).