A worksheet note ends halfway through a sentence, even though Wrap Text is on. Before typing the missing words again, select the cell and inspect its complete value in the formula bar. The text may be intact but hidden by the row’s height.
Adjust the space before changing the content
For desktop Excel on Windows, Microsoft documents Home → Alignment → Wrap Text. Wrapping follows the column width, so first choose a width that suits the sheet. Then select the affected cell or range and use Home → Cells → Format → AutoFit Row Height. A row with a fixed height may need this separate adjustment.
Try a copy of a sheet with an unmerged cell containing three short sentences. After adjusting the row, check that all three are visible and that the formula-bar value is unchanged. Narrow the column slightly and check the last sentence again: the same text may now occupy more lines.
Check merged cells separately
Microsoft lists merged cells as another reason wrapped content may remain hidden. Do not assume AutoFit will resolve that layout. Work in a copy and adjust the row manually if needed; do not unmerge a structured table blindly.
After saving, reopen the workbook and inspect the affected row and its neighbours. If you will print it, also check print preview. Seeing all the text in a cell does not prove that the whole table fits the printed page. These steps concern Microsoft 365 and supported desktop versions listed in the linked help; menu placement differs across platforms.