Capricorn: trust is a working relationship first
Capricorn often builds intimacy backwards compared to everyone else. Rather than confiding first and relying on you later, they prefer to rely on you in some practical way first, and confide only once you've proved reliable. This is why Capricorns so often form their deepest friendships with colleagues, neighbours and people they've been through a logistical nightmare with.
They are also wary of people who are effusive early, because enthusiasm is cheap and following through is not. If you want a Capricorn to open up, be useful and be unflashy about it. Then wait. The sentence you eventually get, the one that starts "actually, I've been finding things hard", is a significant event, and should be treated as one.
Virgo: afraid of being too much, and of being seen badly
Virgo's slowness to trust is rarely suspicion of other people. It's self-consciousness. Many Virgos carry a quiet fear that if someone sees the full extent of their worries, their mental lists, their habit of rehearsing conversations, they'll be considered difficult. So they offer help instead of needs, and stay busy being the dependable one.
The thing that opens a Virgo up is not reassurance in the abstract, but being met without comment on a bad day. Someone who notices they're frazzled and simply makes tea, does a task, and doesn't analyse them out loud. Virgos tell the truth to people who don't make a project out of them.
