You would like to see someone, but the message feels easier to send if it contains a practical excuse. You ask a question you could answer yourself or offer to return something that does not need returning yet.
Try naming the wish directly and modestly. “I would enjoy some company this weekend. Would you like to meet for lunch?” gives the other person a clear invitation without asking them to solve your whole emotional state.
Choose a plan and a person appropriate to the relationship. A close friend may welcome a more personal explanation; a newer acquaintance may find a simple activity invitation easier to answer. Honesty does not require the same level of disclosure in every connection.
Leave room for their circumstances. A decline can be disappointing without meaning the request was wrong. If they suggest another date, consider it. If they are unavailable, you can seek another source of company rather than making one person's answer carry the entire weekend.
You can also be clear about the kind of time you want. A quiet conversation, a lighthearted outing and practical company while doing a task are different invitations. The detail can help someone decide whether they have the right kind of attention available.
Avoid apologizing for the ordinary fact of wanting connection. People often enjoy being asked, particularly when the invitation is specific and allows a comfortable answer. They may not know you would like to meet if you continually present yourself as having no need for company.
Make the request specific enough that the other person can picture the time together. “Would you like to sit with me for a coffee after the appointment?” is easier to answer than a hint that you might be around. If you mainly want listening rather than solutions, say that too. The request gives them a chance to offer the kind of company you would actually find helpful.
Have another way to care for the evening if they are unavailable. That might mean contacting someone else, choosing a familiar outing or making a quieter plan at home. An alternative does not make the first invitation insincere. It simply keeps one person's schedule from carrying the whole weight of how the day turns out. You can want a particular friend's company without requiring them to be available whenever the wish arises.
The message can remain small: a wish, a possible plan and space for a reply. It does not define you as lonely or dependent, and it does not turn the other person into a solution. It simply makes visible one of the ordinary ways friendship happens—someone would like to share a little time and decides to say so.
A little more room to be yourself.