surname 氏 (683a) + a drop 丶 (22a) = settle down 氐

In some typefaces you will see the older form of this character where the dot is replaced by a (very) short horizontal line.

Her fiancé has been a playboy, so she will only marry him if he will sign his surname in a drop of his own blood, to swear that he is now ready to settle down. / [No pronunciation needed]