B1 爱上（某人），（与某人）相爱
to start to love someone romantically and sexually
I was 20 when I first fell in love. 我20岁的时候第一次谈恋爱。
He isn't the first boy to fall in love with her and he certainly won't be the last.
The plot involves a lawyer who falls in love with her client.
After falling in love during the filming of their last movie, the couple have just announced their engagement.
They met and fell in love while they were both training to be pharmacists.
See also: love noun (LIKING SOMEONE)