This is the 4235th most frequent Japanese word.
会え
"会え" means "to be able to meet."
The word "会え" is used here in the phrase "会えて", expressing the act of having met or been able to meet your friend.
友達に会えてとても嬉しい。
I'm very happy to meet my friend.
"会え" in "会えなかった" denotes the inability to meet someone due to a specific context or period.
長い間会えなかったけれど、ようやく会うことができた。
Although we couldn't meet for a long time, we were finally able to.
"会え" is found in "会える", indicating the possibility or hope of meeting someone in the future.