certainly

'Could you help me with this heavy suitcase?' 'Certainly, I'd be happy to.'

(Chinese) “你能帮我提一下这个沉重的行李箱吗？”“当然可以，我很乐意。”

He will certainly be at the meeting tomorrow, as he never misses one.

(Chinese) 他明天肯定会参加会议，因为他从未缺席过。