In a friendly manner you tell them what Bitcoin means to you. Perhaps sit down with them and go through an introductory video on YT that explains what BTC is.

After doing this she will either take your guidance on board and investigate further or she won't. You can't force people to liking things.

And no matter what happens, if she doesn't like BTC or even if she actually does start putting a % of her monthly salary into it she will still not sleep with you. Sorry mate.