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What I’m trying to do
I am trying to include both bold and italics in the same senrtence.
.Now she had on a long-sleeved garment; for in this manner the virgin daughters of the king dressed themselves in robes. Then his attendant took her out and locked the door behind her.
19. Tamar put ashes on her head and tore her **long-sleeved ** garment which was on her; and she put her hand on her head and went away, crying aloud as she went.
I’m taking a guess here that your problem is that the second sentence
is not italic in Obsidian.
I think this happens because Obsidian makes this a numbered list item because of 19.
You can escape that formatting by putting a backslash ( \ ) in front of the number.
*Now she had on a **long-sleeved** garment; for in this manner the virgin daughters of the king dressed themselves in robes. Then his attendant took her out and locked the door behind her.
\19. Tamar put ashes on her head and tore her **long-sleeved** garment wich was on her; and she put her hand on her head and went away, crying aloud as she went.*
Or instead of using the backslash you could remove the space behind 19.
Above is the text properly quoted, and I do believe @Olondre is right that the 19. is causing some issues in the live-preview mode, where there is a slight issue.
However, this text is two distinct lines, with some newline before the 19., and they tried using _ ... _ over multiple lines, which never is a good idea. So it’s not just bold and italics over multiple sentences, but over multiple lines.
Solution, is either to use backslash in front of the 19. as Olondre suggested, or to make each line italic on its own.
CommonMark seems to allow emphasis spanning a line break (probably not a paragraph), but I agree it’s best to avoid it (also, Obsidian’s nonstandard default rendering of line breaks may interfere). I’d emphasize each line separately as holroy suggests.
I’m not sure if the “19.” counts as a list item — if there’s an “18” (or other number) before the period that starts the first line, then it does. But if not, it shouldn’t. But even if it’s not it might affect the highlighting in Live Preview and mess things up (for another case where that happens, see text inside single brackets).