Does true love really exist?

Yes!!! Absolutely. Been married to my one true love for 19 years!

"True love"
I tend to think this movie didn't really portray anything out of the ordinary.
Think about it.
Most couple have a fun, dreamy eyed honeymoon phase in which they are giddy and madly in love with each other.
He hadn't even asked her to marry him yet.
Many couples are giddy in love at that point....it is after ten years of marriage....twenty years of marriage and life and work, responsibilities, bills, kids, getting bored with each other and bad boundaries that things can fade.

He basically goes from being giddy in love and ready to propose...spending a couple of weeks with the family in the 90's to finding the girl he wanted to marry still. It was about 2 weeks time to him. The 50 years just got blacked out.
For her, she comes out of coma.....Daniel has vanished. I'm sure she grieved.....she marries another man and apparently has love, sex, intimacy, fun, vacations, adventures, drama and issues for 40 years plus (did it say how long she was in coma?) Then after living fully all those years she is alone....a widow this old, old flame shows up.
He went from young to old man in a few days. He went from having a young, hot love to and old, old lady in a week!

Poor guy.

Anyway....enough time had not passed for his feeling to change at all.

Yes. It's rare, but it does exist.