feign, fain

Feign or feign means to sham or pretend--
He tried to feign illness to avoid school.
It took all of his willpower to feign interest in the proceedings.

Fain or fain ( rhymes with feign ) means prefer to, or willingly--
He would fain be left out of the fray.
Forsooth, he would fain have remained at home.

Now that you know that, you can say--
"The soldier planned to feign an injury, as he would fain be sent back home."

Note--"feigned" is the past tense ( yesterday, or some time ago ) of "feign"--
He feigned interest in what she was saying, but was really watching someone else.
Not to be confused with "faint", meaning slight or weak--
"Faint heart never won fair maid."
Faint also means to pass out or lose consciousness--
He tried not to faint at the sight of blood, because he wanted to be a doctor.
Not to be confused with "feint" ( rhymes with faint ), meaning a move meant to trick or deceive--
The bombardment was a feint meant to conceal the movement of the troops.
Note # 2--"fane" ( rhymes with feign and fain ) is an old-fashioned word for a church or temple.