Not sure know how to join these two sentences together

[Kwfine]

Hi, teachers

I would like to ask how to join the following sentences together:
(1) With his 18 years of working experience,
Peter is confident that he will help the new comers to develop the skills necessary for the company business.
(2) With his 18 years of working experience,
Peter is confident that he will help certify his colleagues.

I am not sure if this is correct:
With his 18 years of working experience,
Peter is confident that he will help the new comers to develop the skills necessary for the company business, and that he will help certify his colleagues.

Please correct me if I am wrong, teachers.

Thank you.

Kitty
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各位前輩安安, 我是kitty喔!

[Mister Micawber]

With his 18 years of work experience, Peter is confident that he will be able to help newcomers develop necessary skills and help colleagues gain certification.
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Native English teacher at Mister Micawber's

[Kwfine]

[Mister Micawber]

It is often a style choice. In your last example, the two ideas are two different views of the same point, and 'and that' sets up the distinction better. In your earlier sentence, it is just a list of 2 things he will do.
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Native English teacher at Mister Micawber's