4 sentences

1. 我向国旗宣誓效忠。

   wǒ xiàng guó​qí xuān​shì xiào​zhōng.

   I pledge allegiance to the flag.

   Source: OpenSubtitles

2. 他宣誓向祖国效忠。

   tā xuān​shì xiàng zǔ​guó xiào​zhōng.

   He swore an oath of allegiance to his motherland.

   Source: Dong Chinese Dictionary

3. 效忠于我的儿子。

   xiào​zhōng yú wǒ de ér​zi.

   Swear loyalty to my son.

   Source: OpenSubtitles

4. 这位骑士发誓要效忠他的国王。

   zhè wèi qí​shì fā​shì yào xiào​zhōng tā de guó​wáng.

   The knight swore an oath of loyalty to his king.

   Source: Dong Chinese Dictionary