It"s a godsend to meet you here.

在這遇見你真是喜出外。

What a coincidence to meet you here.

真巧在這兒碰到你。

Yes. What a coincidence to meet you in Shanghai.

是的。真巧在上海遇到你。

What a pleasant surprise!

真沒想到會遇見你！

This is a pleasant surprise!

真沒想到會遇見你！

Harry, you old bastard! Fancy meeting you here!

真沒想到在這裡遇見你!

Hello there, what a coincidence!

你好，真巧啊！

What a(pleasant) surprise(meeting you here)!

真沒想到會（在這裡）遇見你。

I didn"t expect to meet you here!

真沒想到會（在這裡）遇見你。

I am very glad to meet you.