The problem is you cannot marry with a non-muslim person, so he/she should accept Islam first.
I’m a muslim and as far as I know, there’s no law that forbid you to marry non-muslim. There’s many muslim clerics or saints who are marry a non-muslim in history of Islam.
But to do that, first you need to have a really strong faith so your partner in future will slowly understand and accept Islam by her/his own will. The common understanding that seems to not marry a non-muslim by many muslims because is not an easy path to have a relationship with different faith. Especially family and tradition on both side.
The most common cases about this are men muslim married a woman non-muslim. On the opposite, is very rare cases that happen in history of Islam. Some (fiqh) law by clerics forbids woman muslim to married a men non-muslim, and some allowed that with requirement the woman need to have a strong faith first.
I have many friends who’s their parents married with different religion (islam and christian, islam and shinto, islam and confucius). I admit is not an easy path than married with same religion as far I can see in my own cases, but I respect their choice…