When someone thanks you for help, they are trying to express gratitude. If you just say 「 No problem」, or 「It’s nothing」, it belittles and devalues their gratitude.
當有人為你的幫助感謝你的時候，他們想表示感恩，不過如果你說「 No problem」, 或者 「It’s nothing」, 這會貶低他們的感恩。
You can say 「 You’re welcome」, but this isn’t the best response.
你可以說You’re welcome，不過這不是最好的回答。
The best response is: "My pleasure".
It is a more polite and positive response to 「Thank you.」 It is similar to "You’re welcome," but a lot more positive.
We use it in formal conversation when someone thanks you for doing a favor, and you want to respond in a way that tells them that you were very happy to help and that you enjoyed it.
「我的榮幸」是對「謝謝」的一種慣用的回應。它類似於「不客氣」，但更有禮貌，語氣更強調。
在正式的談話中，當有人感謝你的幫忙的時候，而且你要以一種告訴他們很高興能幫助他，並且很樂意幫他的方式作出回應，你可以說 「 My pleasure」.
Let's see some real life examples:
On a talk show
Talk show host: Thank you for being on the show with us today.
Guest on show: My pleasure.
In a job interview
Job applicant: Thank you for taking the time to meet with me. I really enjoyed talking with you.
Employer: It was my pleasure. Thanks for coming.
Phone call between two mothers
Mother A: Thank you so much for taking Jimmy to the park with you.
Mother B: It was my pleasure. We enjoyed his company.