How to wire a 230VAC motor with 4 wires. Model is: YDK139-300-4 300w
I would connect N to the top wire with the symbol in the circle. I believe that symbol is an over-temperature protection device. Connect L to H, M, or L for high, medium or low speed. N and L can probably be interchanged with no bad effect.

The direction of rotation is indicated by the arrow on the left with "ROT" above it. The motor can not be reversed because the connections necessary to do that are apparently permanently connected inside the motor. The motor likely does not produce very much starting torque. It is likely designed to drive a fan.

The winding connected to the capacitor is the auxiliary or start winding. Since the capacitor is permanently connected, the motor is called a permanent split capacitor (PSC) motor. Also since the capacitor is not disconnected after starting, the start winding is called an auxiliary winding.

The coil with the H, M, and L connections seems to be the auxiliary winding. Changing the connections changes the voltage applied to the main and auxiliary windings simultaneously. That is a somewhat unusual configuration. With that design, it appears that the motor could not be reversed even if all of the connection points were available for changing connections.