What signal word would you use to emphasize a point?

Using "My main concern is..." effectively emphasizes a point because it directly focuses the reader's attention on a specific issue or topic that is significant within the context of the writing. This phrase sets the stage for a clear assertion or argument, making it apparent that the following information is of paramount importance. In professional communication, especially in medical or occupational contexts, clearly identifying and emphasizing concerns can help ensure that crucial points are understood and addressed appropriately.

In contrast, while "Moreover" can introduce additional information and strengthen an argument, it doesn't inherently signal emphasis on a singular point. "However" establishes contrast and is more suited for presenting an alternate viewpoint rather than emphasizing a particular concern. "Now," although it can signify a shift in topic or focus, does not lend itself to emphasizing a specific point as clearly as "My main concern is...".