他们很高兴又见面了用英语怎么说

They are so happy that they meet each other again.

They feel very happy to meet each other again.

第一句用了"so ...that..."句型.
第二句简单一点..

I am glad meeting you again!

They are glad to meet each other again.

Nice to see you again!

I am glad meeting you again!

They are(were) glad to meet again.