Immortality Spell

I want a spell that could make me immortal but I don't know how I'd test if it works...

There is only one way to become immortal. Have children. Then your genes and DNA will go on. There is no spell that will make you live forever!

Lame.

Guess I'll have to use my powers of extreme seduction. ;)

Well, if you'll allow me a moment of nitpicking...

Achilles is immortal, not because he had kids, but because he is still talked about to this day, thousands of years after he died. Being immortalized is a type of immortality.

But, ya... that's just me nitpicking. Brysing is correct on a more literal note.

There is no ritual/spell to make you immortal on the physical plane

There is no way to make yourself immortal through the use of spells and magic. Your physical body is constantly aging and will eventually wear out and you will die. No magic will change that. Only our spirit is immortal, not our physical self.