Answer by Ali Shakiba for How do I break a string in YAML over multiple lines?

To preserve newlines use |, for example:

Key: |  This is a very long sentence  that spans several lines in the YAML  but which will be rendered as a string  with newlines preserved.

is translated to "This is a very long sentence‌**\n** that spans several lines in the YAML‌**\n** but which will be rendered as a string‌**\n** with newlines preserved.\n"