Timeline Reset After Falling in Love

Sort of. The ML is from ancient times, but can project to the present in his dreams. He meets the FL in the present and falls in love. When some magic involving a lamp sends the FL back to ancient times, a comet somehow causes them to lose their memories of each other... so pretty close to a timeline reset + memory loss, just in a super convoluted way. 

Sort of. 

The leads fall for each other in high school, but the ML basically tells the FL that he will hold off from officially asking the FL to be his girlfriend until after the university entrance exam so as to not distract her from her studies. She agrees and makes it pretty clear that she will say yes when he does ask. But circumstances force them apart before that day can come.

Then the FL becomes part of an experiment that replaces her memories with memories of a false life where she didn't know the ML. When she escapes from the experiment, she believes that she has travelled through time and space from a different world that was in the year 2025 to the ML's world where the year is 2018. She has no memories from her real life, including the time she spent with the ML.