If you are delighted, you are extremely pleased and excited about something.
I know Frank will be delighted to see you.
我知道弗兰克见到你会非常高兴。
If someone invites or asks you to do something, you can say that you would be delighted to do it, as a way of showing that you are very willing to do it.
'You have to come to Todd's graduation party.'—'I'd be delighted.'
“你一定要来参加托德的毕业派对。” “非常乐意。”