Vanishing Time: A Boy Who Returned (2016)

Vanishing Time: A Boy Who Returned, has similar aspects to The King: Eternal Monarch, these aspects are:
-At a certain point the ML is stuck inside a world where time is frozen, and in both stories the MLs are the only ones who still go through time.
-in both stories, the ML is going through this time, in hopes of seeing the FL again.

Both deal with time manipulation in different ways.
Will you be there?" Shows how by changing your past, your entire future can be effected, as "Vanishing Time" shows how time can steal everything away.
These movies have completely different stories, but both are getting the same message across. How time is unpredictable and limited.

it is similar with the one is still younger and the other one grow

Because of circumstances out of their control, the main leads of both movies find time slipping away from them.

Both deal with time manipulation.

Love You Forever is more romantic.

Both have sad themes revolving around time running out.

If you like the time-travel themed movie and drama, "Vanishing Time" is a must-watch.
The plot twist are different however they have the same feel.