Is HelpBase a good name for marketplace that connects mentors and mentees?

The name makes it sound like a source of information, like a wiki. Probably because of the "Base" suffix. If you want a descriptive name, you should probably make it sound more like a marketplace/meeting place than a database.

you might want to give yourself some room to pivot in the future.

It feels awkward to hear mailchimp advertising that they do more than mail but not so weird to use stripe's or google's many products.

Yes sounds good!

To echo some startup guru advice, there's no such thing as a good name, only a bad name (who would have thought Google would have worked?). As long as a name isn't horrendous, it's good enough and you shouldn't spend too much time focusing on it.

Good enough, yes. Don't let perfect be the enemy of good!

MentorCruise.com sure is 😁

I've been doing this for a few months now, let me know if you need advice

I don't know what makes a good name. But I do know when I see a good landing page because it's completely evident, above the fold, what the value prop is.

For example, what are an "airbnb"? But when I hit the airbnb.com landing page it leaves nothing to the imagination: a familiar travel form entitled "Book unique homes and experiences."