A little love with poison?

Here I try to interpret what an ex said to a hopeful.

I try not to dwell too much into politics but this bit of poetry from former PM Goh Chok Tong caught my eye. What a lovely day to talk about love since it is Valentine's Day. Goh Chok Tong was posting on his Facebook about Chan Chun Sing (the previous person who was touted as PM candidate). So Goh was "impressed" by a speech by Chan, which looks good initially.

However, that last line "one swallow does not a summer make" leaves much room for imagination. Well Wiki explains it as "One instance of an event (such as the arrival of a single bird) does not necessarily indicate a trend". So what does it mean?

In my view, Goh was telling Chan that he still has a long way to go in terms of political maturity. While Chan may have made one good speech, he is far from having proved himself to be of PM potential. That Goh can really still be cheeky. So what do you think the proverb meant?