build up (one's) hopes
To cause one to become excited at the prospect of something happening. If you build up Sadie's hopes about going to the carnival tonight, she'll be disappointed if we don't go. Don't build up his hopes about seeing Aunt Jen this weekend—I hear she's having car trouble.
raise (one's) hopes
To cause one to become excited at the prospect of something happening. If you raise Sadie's hopes about going to the carnival tonight, she'll be disappointed if we don't go. Don't raise his hopes about seeing Aunt Jen this weekend—I hear she's having car trouble.